Pairs (P-VOLs and S-VOLs)
XP Continuous Access performs remote copy operations for pairs created by the user. Each XP Continuous Access pair consists of one primary volume (P-VOL) and one secondary volume (S-VOL), that can be located in different storage systems. The XP Continuous Access P-VOLs are the primary volumes (LUs) that contain the original data, and the XP Continuous Access S-VOLs are the secondary or mirrored volumes (LUs) that contain the backup or duplicate data. The primary and secondary volumes must have the same format and capacity (and a SCSI path definition is required). During normal XP Continuous Access operations, the P-VOL remains available to all hosts at all times for read and write I/O operations. During normal XP Continuous Access operations, the RCU rejects all host-requested write I/Os for the S-VOLs. The S-VOL write enable option allows write access to an S-VOL while the pair is split and uses the S-VOL and P-VOL differential data to resynchronize the pair (see S-VOL Write Option (page 18)). XP Continuous Access supports the basic logical unit types available on the storage system (for example, OPEN-3, OPEN-8, OPEN-9, OPEN-E, OPEN-L, and OPEN-V). See Logical Unit Types (page 52) for further information on LU requirements and support. XP Continuous Access supports a maximum of 32,768 pairs (entire storage system). The maximum number of pairs is determined by the number of LDEVs, not LUs. Therefore, if the XP Continuous Access pairs include the LUSE pairs, the maximum number of pairs decreases because a LUSE volume consists of multiple LDEVs. When the HP StorageWorks RAID Manager command device is defined, the maximum number of pairs in the storage system is reduced to 32,767. When XP Continuous Access Journal for Mainframe and XP External Storage Access Manager Software pairs exist together in the same disk subsystem, the sum of the XP Continuous Access, the XP Continuous Access Journal, and the XP External Storage Access Manager Software pairs is used to calculate the maximum number of pairs.
Synchronous Consistency Groups
An XP Continuous Access Synchronous consistency group is a user-defined set of volume pairs. If you specify a consistency group for XP Continuous Access Synchronous pairs, you can issue a command for each group and can ensure the consistency of pairs in the same group. XP Continuous Access Synchronous pairs or TrueCopy for Mainframe synchronous pairs can be registered in an XP Continuous Access Synchronous consistency group. If an XP Continuous Access Synchronous pair and a TrueCopy for Mainframe synchronous pair are registered in the same group, you can ensure the consistency between an XP Continuous Access Synchronous pair and a TrueCopy for Mainframe synchronous pair in the same group. If only XP Continuous Access Synchronous pairs or only TrueCopy for Mainframe synchronous pairs are registered in the group, you can ensure the consistency of the pairs in each group. For more information on a TrueCopy for Mainframe synchronous pair, see the Hitachi TrueCopy for Mainframe User Guide: HP XP24000 Disk Array, HP XP20000 Disk Array. If the split command (Pairsplit-r or YKSUSPND) is issued to the corresponding consistency group and if the I/O processing on some volumes in the consistency group has not finished, the split operation to the XP Continuous Access volume pair is executed after the I/O processing and the data transfer to S-VOL have finished. Also, the split operation to the TrueCopy for Mainframe volume pair is executed after the track processing of the volume that is in I/O processing and the data transfer to R-VOL have finished. Even if the suspend operation caused by system failure occurs to the pairs in a consistency group, the suspend operation to the volume is executed similarly with ensuring the data consistency of the pairs in the corresponding group. You can ensure consistency of data of volumes in the same DKC. XP Continuous Access allows you to configure up to 128 consistency groups (00-7F) for each MCU. For detailed information about synchronous consistency groups, see XP Continuous Access Synchronous Consistency Group Operations (page 24). XP Continuous Access synchronous pairs in the Synchronous consistency groups can be defined and operated only by RAID Manager. TrueCopy for Mainframe synchronous pairs in the Synchronous consistency groups can be defined and operated only by Business Continuity Manager. For details, see the HP StorageWorks RAID Manager User Guide or the HP StorageWorks for Business Continuity Manager Software User Guide. To define or operate TrueCopy for Mainframe synchronous pairs in the Synchronous consistency groups, install the TrueCopy for Mainframe software. An XP Continuous Access Synchronous consistency group and a TrueCopy Open/MF consistency group described in the Hitachi TrueCopy for Mainframe User Guide are the same. For further information on a TrueCopy Open/MF consistency group, see the Hitachi TrueCopy for Mainframe User Guide: HP XP24000 Disk Array, HP XP20000 Disk Array. You must use the same consistency group number when XP Continuous Access Synchronous pairs and TrueCopy for Mainframe Synchronous pairs are registered in the same XP Continuous Access Synchronous consistency group. Therefore, you must decide beforehand the consistency group number by both RAID Manager and Business Continuity Manager. Specify the unused consistency group number. Before you start the operation, define the pair specifying the consistency group number with RAID Manager and Copy Group Attributes (TC) window of Business Continuity Manager. For further information about the Copy Group Attributes (TC) window, see the HP StorageWorks Business Continuity Manager Software User Guide.

Continuous Access pair. This option can only be specified using the XP Continuous Access software (not RAID Manager). The initial copy priority option allows you to specify the order in which the initial copy operations are performed when creating/resynchronizing multiple XP Continuous Access pairs. This option can only be specified using the XP Continuous Access software (not RAID Manager). The Maximum initial copy activity option allows you to specify the maximum number of concurrent initial copy and resync operations that each MCU can perform (not pair-specific). This option can only be specified using the XP Continuous Access software (not RAID Manager). The Round Trip Time option is a reference value used for automatic control of the initial copy pace and for avoiding the remote I/O response time to the update I/Os being affected by initial copy while the copy operation is in progress. The value of Round Trip Time is compared with the remote I/O response time, and then, the copy pace is controlled when the difference between the two values is large. If the difference between the remote I/O response time and the value of Round Trip Time is large, for example, the remote I/O response time is 500 ms but the value of Round Trip Time is 1 ms, the copy pace will slow or sometimes the initial copy will interrupt, so that the initial copy process does not occupy the entire bandwidth of the lines. On the other hand, if the difference between the remote I/O response time and the value of Round Trip Time is small, for example, the remote I/O response time is 5 ms and the value of Round Trip Time is 1 ms, the initial copy runs at a specified pace. The default value of Round Trip Time is 1 ms. Specify an appropriate value at the Round Trip Time when the distance between MCU and RCU is long or there is a delay caused by the line equipment. If the initial copy operation is performed with the default value of Round Trip Time instead of the appropriate value, it may take unexpectedly long time to complete the initial copy operation.

Update Copy Operation

An update copy operation occurs when the host issues a write I/O operation to the XP Continuous Access P-VOL pair. The update copy operation duplicates the P-VOL write I/O at the S-VOL to keep the pair synchronized. XP Continuous Access provides two modes for update copy operations: synchronous and asynchronous. The update copy mode is specified when you add an XP Continuous Access pair and cannot be changed. For the synchronous update copy mode, the MCU ensures that the P-VOL and S-VOL are synchronized at all times. The MCU does not return a final ending status for the P-VOL write I/O until both the P-VOL write and its associated update copy operation at the RCU are complete. For the synchronous mode, the MCU starts the update copy operation when it receives any of the following: A write command whose data length is short enough not to pass the track-end Write data to the track-end whose total length is long enough to pass the track-end Write data to the last track for the command

Usage Monitor Window

The Usage Monitor window (see Figure 29 (page 79)) displays the remote copy I/O statistics for all LDEVs to be monitored on the connected storage system, displays the status of remote copy usage monitoring, and allows you to perform the XP Continuous Access usage monitor operations (see Usage Monitor Operations (page 109)).
Figure 29 Usage Monitor Window
The Usage Monitor window displays:
Item Monitoring Switch Description Allows you to see whether monitoring is on or off. Monitoring Switch displays Enable when monitoring is on, and displays Disable when monitoring is off. When monitoring is stopped, the usage monitor graph is closed. The usage monitor graph can only be displayed when monitoring is running. Gathering Interval Update Graph Allows you to see the data collection interval for usage monitoring. Displays the most recent data sample time for the data on the graph. Displays the remote I/O statistic information and the status of remote copy monitor.
NOTE: The settings of Usage Monitor are linked with the settings for the monitoring switch in the Monitoring Options window of Performance Monitor. If you start or stop monitoring or change the value of Gathering Interval with the Usage Monitor window of XP Continuous Access, the status of monitoring or the value of Gathering Interval on the Performance Monitor window is also changed. If the settings for the monitoring switch are changed from the Monitoring Options window of Performance Monitor, the settings on the Usage Monitor window of XP Continuous Access are automatically changed.

History Window

The History window (see Figure 30 (page 80)) displays the history information for the XP Continuous Access pairs and allows you to perform XP Continuous Access history operations. The history
XP Continuous Access Windows 79
information includes the records for the main status changes (for example, pair creation, and release) of the XP Continuous Access pairs. See History Operations (page 113) for information and instructions on performing XP Continuous Access history operations. To display the latest information for the History window, click File, and then Refresh on the menu bar of the Remote Web Console main window. The latest information on the History window is not updated by clicking another tab and then clicking the History tab again. When you can access the local file in the Remote Web Console computer, you can download the history file. When you cannot access the local file, the Export button is not displayed on the History window. For further information on the settings for accessing local files, see the HP StorageWorks XP24000/XP20000 Remote Web Console User's Guide. If the pound or gate symbol (#) is added to the end of the device ID (00:00:3C #, for example), the LDEV that the number indicates is an external volume. For details on external volumes, see the HP StorageWorks XP24000/XP20000 External Storage Software User's Guide. If an X mark is added to the end of the device ID (00:00:3C X, for example), the LDEV that the number indicates is a Thin Provisioning virtual volume. For details on virtual volumes, see the HP StorageWorks XP24000/XP20000 Thin Provisioning Software User's Guide. Figure 30 History Window

Adding Consistency Groups
The Add CT Group dialog box (see Figure 39 (page 105)) allows you to add consistency groups and select the options for the new groups. To open the Add CT Group dialog box, click the Asynchronous Operation tab, click Display All or Not Used in the tree, select the group(s) to be added, right-click the group(s), click CT Group Operation, and click Add CT Group.
104 Performing XP Continuous Access Configuration Operations
Figure 39 Add CT Group Dialog Box
MCU-RCU Path: Indicates the path type (fibre) for the remote copy connections. Currently, you cannot change the path type. Offloading Timer (sec.): Allows you to specify the amount of time for monitoring the transfer of data to a sidefile between 0 and 255 seconds in 1 second increments. The default setting is 90 seconds. Enable Inflow Control: Allows you to enable the inflow control. To enable the inflow control, click the check box. By default, the check box is selected. Before changing this option, you should release or suspend pairs in the selected consistency group. Time Out (Copy Pending) (min.): Allows you to select the maximum delay allowed for XP Continuous Access Asynchronous copy (none or from 1 to 15 minutes, none = no timeout for copy pending). The default setting is 5 minutes. If the delay between the XP Continuous Access P-VOL update and the corresponding S-VOL update reaches the specified time, the RCU will suspend all S-VOLs in the group. A timeout occurs when the RCU was not able to settle a recordset within the specified time, or when the RCU has not had any communications from one of the MCUs in the group within the specified time. Time Out (RCU ready) (min.): Allows you to select the maximum delay allowed for re-establishing MCU-RCU communications following an MCU power-off (none or from 1 to 10 minutes, none = 0 minutes). The default setting is 5 minutes. If the MCU is not able to re-establish communication with the RCU within the specified time, the MCU suspends all P-VOLs in the group. To add one or more consistency groups to the connected MCU: 1. 2. 3. Make sure that the async options are configured as desired. Select the LDKC where the desired consistency group belongs or select Not Used from the tree in the Asynchronous Operation tab to display the unused consistency groups in the list. Select the (unused) consistency group(s) that you want to add. The XP24000/XP20000 disk array supports up to 128 consistency groups (00-7F) per LDKC and allows you to use up to 128 consistency groups per entire storage system. The XP12000/XP10000 disk array supports up to 128 consistency groups (00-7F). Right-click the selected group(s), click CT Group Operation, and then click Add CT Group to open the Add CT Group dialog box (see Figure 39 (page 105)). On the Add CT Group dialog box, select the desired path type and group options (copy pending timeout, RCU ready timeout). You will not be able to modify the path type of the group after you assign a pair to the group. 6. Click Set to close the Add CT Group dialog box. (Click Cancel to cancel the add group operations.) The preview list displays the requested add group operation(s).

To start the operation(s), click the Apply button. If an error occurs in the setting, an error code is displayed in the Error Code column in the preview list. To display an error message, select one LU, right-click, and click Error Detail. After you see the error message(s), click OK to close the error message.
XP Continuous Access Snapshot Function
The XP Continuous Access snapshot function writes the user-selected XP Continuous Access pair status information to a text file on the SVP, which you can then download. The status information reported in this file is determined by the selections on the Display Filter dialog box (see Display Filter (page 69)). You can use this function to verify completion of your XP Continuous Access operations. You can use the snapshot function only while client file access is enabled. When client file access is not enabled, the Export button (the button for the snapshot function) is not displayed on the Pair Operation window. For the further information on the client file access settings, see the HP StorageWorks XP24000/XP20000 Remote Web Console User's Guide. Table 30 (page 122) describes the XP Continuous Access Snapshot function. Example of an XP Continuous Access Snapshot File shows an example of an XP Continuous Access Snapshot file. Table 30 Snapshot Function
Data format Target data Termination Text (See the example shown below) The XP Continuous Access pairs to be reported are determined by the selections on the Display Filter dialog box. When Subsystem or an LDKC is selected in the tree, you can stop the process by clicking the Cancel button in the dialog box displayed during the execution of the Snapshot function. Each time the Export command is selected, the previous status data is deleted and the new data is written.

Initialization

Performing XP Continuous Access Pair Operations
Example of an XP Continuous Access Snapshot File
The following is an explanation of the fields: (1) Port number (2) GID and host group name (3) LU number (4) LDEV number (5) Status of the pair (6) Suspend sub status (7) Serial number of other CU (8) Other CU SSID or Path Group ID (9) Port number of other LU (10) GID of other LU (1 LU number of other LU 1) (12) LDEV number of other LU (13) Pair mode (14) Fence level (15) Differential data setting (16) Consistency group number (17) Error level (18) Copy priority (19) Pairing progress (%) (20) Quorum Disk ID (21) Quorum Disk status (22) CLPR number and CLPR name

P-VOL of Pair LUN 03 LUN 05 LUN 00 LUN 04 LUN 01, 02 Priority 5
The MCU immediately starts the initial copy operations for LUNs 003, 005, 000, and 004, immediately; starts LUN 001 when one of the first four initial copy operations is complete, and then starts LUN 002 when the next initial copy operation is complete. If more XP Continuous Access pairs are created, the MCU also prioritizes the initial copy operations by the time requested so that all pairs in the first group are started before any pair in the next group is started. If the time-out error occurs during the Paircreate operation, the copy operation may not be executed correctly in the order that you have set with the Priority parameter. The time-out error may be caused by the CU configuration or a remote copy path error. Review the error, release the pair with the error, and then retry the Paircreate operation.

Pair Options

When you create new XP Continuous Access pairs, you select the pair options on the Paircreate dialog box. You can change the fence level and error level pair options after a pair has been added. You cannot change the difference management or CT group of an existing pair. You need to release and then restart the pair to change these options. P-VOL Fence Level (Synchronous only): Specifies the conditions under which the MCU will reject write operations to the P-VOL, which is known as fencing: never, data, or status (default = Never). This parameter is very important for disaster recovery planning (see Considering the P-VOL Fence Level Setting (page 149)). Never: The P-VOL will never be fenced. If the XP Continuous Access pair is split or suspended, write operations to the P-VOL will be accepted. (The fence level for all XP Continuous Access Asynchronous pairs is Never.) Data: The P-VOL will be fenced when the MCU cannot successfully execute an update copy operation for any reason. Status: The P-VOL will be fenced only if the MCU is not able to change the S-VOL status to suspended when an update copy operation fails. If the MCU changes the S-VOL status to
suspended, subsequent write operations to the P-VOL will be accepted, and the MCU will keep track of all P-VOL updates while the pair is suspended. CT Group (Asynchronous only): Specifies the consistency group number for new pairs. All XP Continuous Access Asynchronous pairs must be assigned to a consistency group. To change the consistency group to which a pair is assigned, you must release and then restart the pair with the desired group selected. Error level (Asynchronous only) (default = Group): Group: When the specified pair is suspended, all pairs in the same group will be suspended, even if the failure affects only that pair and not the entire group. IMPORTANT: Select the Group error level for all pairs that are essential to disaster recovery. Suspended XP Continuous Access Asynchronous S-VOLs with the LU error level should not be used for disaster recovery. LU: If the failure affects only the specified pair, then only that pair will be suspended. A failure that affects an entire group will always result in the suspension of all pairs in the group, as well as all other affected XP Continuous Access pairs.

130 Performing XP Continuous Access Pair Operations
Viewing XP Continuous Access Pair Status
The Detailed Information dialog box (see Figure 51 (page 131)) displays the detailed pair status information for the selected pair. To open the Detailed Information dialog box, click the Pair Operation tab, select a CU grouping, CU, port, or host group from the tree, select the desired pair, right-click, and then click the Detailed Information command. Figure 51 Detailed Information Dialog Box
P-VOL and S-VOL: Port - GID - LUN (lowest LDEV number for a LUSE pair). Device emulation type. Capacity in MB (to two decimal places). The number of blocks.
If the pound or gate symbol (#) is added to the end of the device ID (00:00:3C #, for example), the LDEV is an external volume. For details on external volumes, see the HP StorageWorks XP24000/XP20000 External Storage Software User's Guide. If an X mark is added to the end of the device ID (00:00:3C X, for example), the LDEV that the number indicates is a Thin Provisioning virtual volume. For details on virtual volumes, see the HP StorageWorks XP24000/XP20000 Thin Provisioning Software User's Guide. For P-VOL or S-VOL, the Port - GID - LUN part displays the port number, the host group number, and LUN of the volume that you specified in the remote storage system when creating the pair. If you change or delete the port number, the host group number, or LUN of the volume in the remote storage system, incorrect information will be displayed in P-VOL or S-VOL. Unless you have any special
Viewing XP Continuous Access Pair Status 131
circumstances, do not change or delete the port number, the host group number, or LUN that you specified when creating the pair. CLPR: The CLPR number and the CLPR name of the volume on the primary site are displayed. Group Name: Displays the host group name if the port on the primary site connects a host group. Pair Status: SMPL, COPY, PAIR, PSUE, PSUS, PDUB, Suspending, Deleting, or SSWS. For information on the Pair Status, see Pair Status (page 31). SSWS is also relevant to the XP External Storage Access Manager pair. If the pair is split or suspended, the split/suspended type is also displayed. Pair Synchronized: Progress of the initial copy operation (percentage and progress bar). If the pair is split or suspended, the percentage of synchronized data in the corresponding volume is displayed. This indication is displayed when the selected volume is P-VOL or S-VOL that is in pair status other than COPY. If the corresponding volume is being queued, Queuing is displayed. RCU S/N and ID: Serial number and SSID of the RCU (or MCU if an S-VOL is selected) or Path group ID. Controller ID: Allows you to select the controller ID of the RCU. The controller ID for an XP24000/XP20000 disk array is 5, and the controller ID for an XP12000/XP10000 disk array is 4. The model name is displayed next to the controller ID. MCU-RCU Path: Channel type of the path interface between the storage systems (fibre). Update Type: Synchronous, Synchronous-C, Asynchronous, or XP External Storage Access Manager. Copy Pace: 1-15 tracks. This indication is displayed only when P-VOL is selected. Initial Copy Priority: 1-256. This indication is displayed only when P-VOL is selected. P-VOL Fence Level (sync only): Never, Data, or Status. S-VOL Write: Enabled or disabled for this pair (enabled only when the pair is split). If the corresponding volume is S-VOL and the write operation can be performed on the volume, the status of whether the S-VOL has received the write operation or not is also displayed. If the write operation has already accepted, Enable / Received is displayed. If the write operation has not accepted yet, Enable / Not Received displays. Pair Established: Date and time that the pair was created. Last Updated: Date and time that the pair status was last updated. Pair Copy Time: Time that was taken to copy the pairs. This indications is displayed only when P-VOL in PAIR status is selected. The time that is shown in Pair Copy Time differs from the time that is shown in Copy Time on the History window. The steps to create a pair: 1. 2. 3. MCU receives a request to create a pair. MCU receives a request to start the paircreate operation. The paircreate operation is started according to the conditions of initial copy priority and maximum initial copy activities.

Planned Outage of the MCU
A planned MCU outage does not affect XP Continuous Access Synchronous. For XP Continuous Access Asynchronous operations, the MCU must communicate with the RCU even if there are no P-VOL update I/Os from the primary system. During the power-off sequence, the MCU automatically suspends all XP Continuous Access Asynchronous pairs in the PAIR and COPY states (suspend type = MCU P/S-OFF). During the power-on-reset sequence, the MCU automatically resynchronizes these suspended pairs (pairs with other suspend types are not automatically resynchronized).
Planned Outage of the RCU or Remote Copy Connection
You must split all affected XP Continuous Access pairs prior to a planned outage of an RCU or of a remote copy connection component (for example, switch or channel extender). If you do not split the pairs first, the MCU(s) will detect the communications failure, suspend all affected pairs, and generate SIMs reporting the failures. To perform a planned outage of an XP Continuous Access RCU or remote copy connection component: 1. Identify all XP Continuous Access P-VOLs that will be affected by the equipment outage. You need to know the MCU, CU, and ID (port, GID, LUN) for each of these P-VOLs. a. For an RCU power-off, identify all P-VOLs that are paired with S-VOLs in the RCU to be powered off. b. For a remote copy connection outage, identify all P-VOLs in all MCUs that use the path/component to be powered off. Connect to each MCU that contains affected P-VOLs, and split all affected XP Continuous Access pairs. Make sure to confirm the pair status changes (Pair Operation window or Detailed Information dialog box). Perform the planned outage of the RCU or remote copy connection. When the RCU is fully powered on and ready to resynchronize operations, resynchronize (pairresync) all XP Continuous Access pairs at each MCU. Make sure to confirm the pair status changes.
Planned Outage of the MCU and RCU
When you plan an outage of XP Continuous Access MCUs and RCUs at the same time, the MCUs must be powered off before the RCUs and powered on after the RCUs. To perform a planned outage of an XP Continuous Access MCU and RCU: 1. If an RCU power-on will be difficult to control (for example, Power-Control-Interface setting), you should consider increasing or disabling the Time Out (RCU ready) group option (see Group Options (page 30)) for each XP Continuous Access Asynchronous group with S-VOLs in the RCU(s) to be powered off. Perform the planned outage of the MCU(s) as described in Planned Outage of the MCU (page 145). Do not power-on the MCU(s) yet. If an RCU to be powered off is connected to an MCU that is not powered off, make sure to split those XP Continuous Access pairs before powering off the RCU. Perform the planned outage of the RCU(s) as described in Planned Outage of the RCU or Remote Copy Connection (page 145).

Powering Off/On XP Continuous Access Components 145
Power on the RCU(s). Make sure that they are fully operational and ready to resynchronize operations before powering on the MCUs. Power on the MCU(s), and make sure that they are ready to resynchronize operations. If you split any pairs in step 3, you can also resynchronize (pairresync) those pairs now.
Pinned Track Recovery for XP Continuous Access Volumes
To ensure full data integrity of the pair while recovering the pinned track, use the following procedure: 1. 2. Connect to the MCU of the XP Continuous Access pair that contains the volume with the pinned track, and select the correct CU. Release the XP Continuous Access pair (pairsplit-S) that contains the volume with the pinned track. If you release the XP Continuous Access Asynchronous pair, release only the pair that contains the volume with the pinned track. To release only the XP Continuous Access Asynchronous pair that contains the volume with the pinned track, select LU for Asynchronous Parameters and Delete Range. 3. Perform your usual procedure for recovering data from a pinned track. See the pinned track recovery procedures for your OS, or contact your HP Technical Support service representative for assistance in recovering the pinned track. Restart the pair using the Paircreate dialog box, and make sure to use the Entire Volume initial copy option. Make sure to specify the pair for which the pinned track recovery operation was performed.

7 Usage Scenarios

This chapter describes several usage scenarios for XP Continuous Access. Data Migration Using XP Continuous Access Synchronous (page 147) Point-in-Time (PiT) Data Duplication Using XP Continuous Access Asynchronous (page 148) Using XP Continuous Access for Disaster Recovery Operations (page 148)
Contact your HP service representative for further information on Business Continuity and Disaster Recovery Solutions from HP.
Data Migration Using XP Continuous Access Synchronous
When you need to migrate data for any of the following reasons, XP Continuous Access Synchronous can be used for the data migrated to the other volume. To load data onto new or scratch volumes (for example, new or upgraded storage system), To temporarily move data off an LU to accommodate other activities (for example, repair), or To relocate LUs to balance workloads and distribute I/O activity evenly within and across storage systems for the purpose of improving storage system and system performance.

The data migration has the possibility that the performance decreases and the utilization rates rises as well as the XP Continuous Access synchronous.
Point-in-Time (PiT) Data Duplication Using XP Continuous Access Asynchronous
XP Continuous Access Asynchronous enables you to make Point-in-Time (PiT) duplicates of groups of volumes. The XP Continuous Access Asynchronous Group and Drain pairsplit options can be used together to create a PiT copy, relative to an application, of an entire XP Continuous Access Asynchronous consistency group of volumes. To produce a PiT duplicate of an existing XP Continuous Access Asynchronous consistency group: 1. 2. Stop all host updates to all XP Continuous Access Asynchronous P-VOLs in the group. After all P-VOL updates have completed, split the XP Continuous Access Asynchronous group using the Group and Drain pairsplit options. If you are splitting the group at the main site, issue the pairsplit-r/group command to one P-VOL in the MCU. If you are splitting the group at the remote site, issue the pairsplit-r/group command to one S-VOL in the RCU. The copy pending timeout setting for the group determines the maximum amount of time that the pairsplit-r/drain operation can take (see description of Drain above). 3. When the status of all XP Continuous Access Asynchronous pairs in the group has changed to PSUS, the duplicate set of volumes is complete. If desired, you can restart the application at the main site.
Using XP Continuous Access for Disaster Recovery Operations
The type of disaster and the status of the XP Continuous Access pairs will determine the best approach for disaster recovery. For example, if all XP Continuous Access pairs are in the PAIR state when a total system failure occurs at a single point in time, the S-VOLs are current and recovery is straightforward. Unfortunately, some disasters are not so orderly and involve intermittent or gradual failures occurring over a longer period of time. The user should anticipate and plan for all types of failures and disasters. The major steps in preparing for disaster recovery are: 1. Identify the volumes and groups that contain important files and data for disaster recovery. In addition to supporting XP Continuous Access remote copy operations as well as RAID Manager commands, the storage system provides battery-backed nonvolatile duplexed cache, full hardware redundancy, dynamic sparing, and an advanced RAID-5 implementation to ensure full data integrity in the event of a sudden power outage or other failure. Install the Remote Web Console computer and XP Continuous Access hardware and software, and establish XP Continuous Access operations for the volumes and groups identified in step 1. Make sure to select the proper CUs/ports to access the desired volumes. See System Requirements (page 50) for XP Continuous Access installation instructions. See Performing XP Continuous Access Configuration Operations (page 85) for instructions on performing XP Continuous Access configuration operations. See Preparing for XP Continuous Access Operations (page 50) for instructions on performing XP Continuous Access pair operations.

Using XP Continuous Access for Disaster Recovery Operations 149
P-VOL, but the MCU keeps track of updates to the P-VOL while the pair is suspended. Host failover capability is essential if this fence level setting is used. For disaster recovery, the currency of the S-VOL is determined by using the sense information transferred via host failover or by comparing the S-VOL contents with other files confirmed to be current.

Setting the Fence Level

When a takeover by the S-VOL occurs as shown in Figure 55 (page 150) (two errors have already occurred), Data(V) remains in the rollback process at the secondary host, and full recovery cannot be performed. To avoid this situation, you can define the fence level of the Redo log file as Data, so that the P-VOL returns an error if a data disagreement is expected to occur concerning a write request issued from the host. The Data fence level setting maintains full consistency between the Redo log file and the data file, since no data is written to the data file due to the write error at the log file. However, when the fence level is defined as Data, a write I/O causes an error even when processing has been suspended due to an error at the S-VOL. In this case, a takeover by the S-VOL occurs, and the significance of the duplex system will be lost. Therefore, if you define the fence level as Data, applications must be able to cope with write I/O errors by handling them. Systems that allow disk errors by means of multiplication can function with the Data fence level setting. For example, Oracle multiplies the Redo log file by itself (default = three times). Figure 55 Relationship Between Log File and Data File in PAIR Status
Since most UNIX file systems (excluding JFS and VxFS) have no journal files, the P-VOL fence level should be defined as Never. When a takeover by the S-VOL occurs, fsck is executed on the volume and the file system is cleaned up, even if the S-VOL is undefined at the secondary host. The data that will be lost depends on how much differential data is contained in the P-VOL when the S-VOL is suspended. During operation, error recovery should be performed when the suspended status (PSUE) is detected (when one error occurs).
Transferring Sense Information Between Sites
When the MCU (or RCU for XP Continuous Access Asynchronous) suspends an XP Continuous Access pair due to an error condition, the MCU/RCU sends sense information with the unit check status to the appropriate host(s). This sense information is used during disaster recovery to determine the currency of the S-VOL, and must be transferred to the remote site via the host failover software.

File and Database Recovery Procedures
When an XP Continuous Access Synchronous pair is suspended, or when the MCU fails due to a disaster, the S-VOL may contain in-process data. A data set could be open, or transactions may not have completed. Even if you use the Data fence level for all XP Continuous Access Synchronous pairs, you need to establish file recovery procedures. These procedures should be the same as those used for recovering any volume that becomes inaccessible due to control unit failure. These procedures are more important if the Status or Never fence level settings are used. XP Continuous Access Asynchronous does not provide any procedure for detecting and retrieving lost updates. To detect and recreate lost updates, you must check other current information (for

150 Usage Scenarios

example, database journal log file that was active at the primary system when the disaster occurred). The XP Continuous Access Asynchronous consistency status (group or volume) can be useful when performing this detection and retrieval. Since this detection/retrieval process can take a while, your disaster recovery scenario should be designed so that detection/retrieval of lost updates is performed after the application has been started at the secondary system. You should prepare for file and database recovery by using: Files for file recovery (for example, database log files that have been verified as current). To ensure the currency of these files, use the Data fence level setting for the XP Continuous Access pairs that contain these important files. The sense information will be transferred via host failover.
IMPORTANT: Remote copy and disaster recovery procedures are inherently complex. Consult your HP service representative on sense-level settings and recovery procedures. See Pinned Track Recovery for XP Continuous Access Volumes (page 146) for information on recovering a pinned track on an XP Continuous Access volume.
Switching Operations to the Remote Site
If a disaster or failure occurs at the primary site, the first disaster recovery activity is to switch your operations to the secondary site. The XP Continuous Access Synchronous S-VOLs are recovered individually based on the pair status and P-VOL fence level information for each pair. The XP Continuous Access Asynchronous S-VOLs are recovered based on the pair status and consistency status (at the RCU). The basic procedures for switching operations to the remote backup site are: 1. Record the pair status and fence level of each XP Continuous Access Synchronous S-VOL. Record the pair status and consistency status of each XP Continuous Access Asynchronous S-VOL (displayed only at the RCU). Suspended XP Continuous Access Asynchronous S-VOLs with a consistency status of group are consistent with the other S-VOLs in the group and can be used for disaster recovery. 2. Analyze the currency of the XP Continuous Access Synchronous S-VOLs (see Analyzing the Currency of XP Continuous Access Synchronous S-VOLs (page 152)) and the consistency of the XP Continuous Access Asynchronous S-VOLs (see Analyzing the Consistency of XP Continuous Access Asynchronous S-VOLs (page 152)). Perform file recovery as needed (see File and Database Recovery Procedures (page 150)). At the remote site, connect to each RCU, and release all XP Continuous Access Synchronous pairs. For XP Continuous Access Asynchronous pairs, release all consistent pairs in a group at the same time using the pairsplit-S command with the C/T delete range option. This option prevents you from accidentally using inconsistent pairs for disaster recovery. CAUTION: Once an S-VOL changes to simplex, you cannot distinguish it from a non-XP Continuous Access simplex volume. The XP Continuous Access Asynchronous consistency status is also discarded when the pair is released. 5. 6. 7. If necessary, use the volume manager to change the volume labels of the S-VOLs. Make sure that all required file recovery procedures have been completed before varying the S-VOLs online. At this point, you may start critical applications at the remote site with the previous S-VOLs taking the place of their P-VOLs.

Table 35 Troubleshooting RCU Path Status Problems
Path Status Initialization Failed Description Corrective Action
The link initialization procedure to the RCU Make sure that the MCU and RCU are failed. physically and correctly connected. Make sure that you entered the correct RCU S/N and SSID and path parameters (port, link address, logical address). Make sure the correct MCU port is configured as an initiator port and the correct RCU port is configured as an RCU target port.

Communication Time Out

Communications between the MCU and RCU timed out.
Make sure the RCU is powered on and fully functional (NVS, cache). Make sure that the remote copy connection hardware (cables, connectors, switches, extender devices, communication lines, and all other devices connected to the extenders) are properly configured and functional. Delete the failed path. You may need to change the minimum paths setting or delete the RCU to delete the path. Then add the path/RCU using Edit Path or Add RCU.

Troubleshooting

Table 35 Troubleshooting RCU Path Status Problems (continued)
Path Status Resource Shortage (MCU/RCU) Description The MCU/RCU rejected the establish logical path link control function because all logical path resources in the MCU/RCU are being used for other connections. Corrective Action Delete the failed path, and also delete all paths and RCUs not currently in use. The MCU can be connected to up to four RCUs with up to eight paths to each RCU. Make sure that all MCU and RCU ports are properly configured: Ordinary target ports or RCU target ports for hosts, RCU target ports for MCUs, initiator ports for RCUs; If necessary, connect to the RCU to delete paths/RCUs and reconfigure ports, then reconnect to the MCU. Add the path/RCU again using Edit Path or Add RCU. Serial Number Mismatch The RCUs S/N does not match the specified S/N. Make sure that you entered the correct RCU S/N and SSID and path parameters (port, link address, logical address). Delete the failed path. You may need to change the minimum paths setting or delete the RCU to delete the path. Add the path/RCU using Edit Path or Add RCU. Fibre: Make sure that you entered the correct Controller ID, and that the Fibre Channel topology settings of the MCU and RCU ports are correct. Invalid Port The specified port is not configured as an initiator port, or this path already exists. Make sure the correct MCU port is configured as an initiator port and the correct RCU port is configured as an RCU target port. Make sure that you entered the correct RCU S/N and SSID and path parameters (port, link address, logical address). Delete the failed path. You may need to change the minimum paths setting or delete the RCU to delete the path. Then add the path/RCU using Edit Path or Add RCU. Port number invalid Fibre remote copy is not supported. Communication error RCU Port Number Mismatch The specified port number is invalid. The Delete the failed path. Check the port cable is not connected to the specified port. number or the cable connection, and retry. The microcode on the RCU side does not support the fibre remote copy function. A timeout error has occurred between the MCU and RCU. The specified port in the RCU is physically disconnected from the MCU. Install the microcode that supports the fibre remote copy function on the RCU side. Delete the failed path and retry. Make sure that you entered the correct RCU port number. Correct the port number if necessary. Make sure that the MCU and RCU are physically connected. Make sure that the Fibre Channel topology settings for the MCU and RCU ports are correct. RCU Port Type Mismatch The specified RCU port is not configured as Make sure that the RCU port is configured an RCU target port. as an RCU target port. General Troubleshooting 157

QuickSpecs

Overview

HP StorageWorks Cluster Extension Software
HP offers a range of solutions that protect your valuable information against the threat of downtime making your operations resilient regardless of external or internal events. HP business continuity software solutions provide disaster tolerance to keep your corporate information accessible, and available through adverse events. Any amount of system downtime can mean lost productivity, lost revenue, lost customers, and lost opportunities; HP provides proven technology strategies, and services to reduce your exposure and vulnerability. Defend your mission-critical operations and secure your company's future with HP StorageWorks Cluster Extension. Cluster Extension Software offers protection against application downtime from fault, failure, or site disaster by extending a local cluster between data centers over metropolitan distance. CLX reinstates critical applications at a remote site within minutes after an adverse event and integrate with the OS clustering software (MS Cluster Service in Windows and native clusters on RedHat and SuSe in Linux), HP StorageWorks Continuous Access software on EVA/XP/P9000 to automate failover and failback between sites. This dual integration enables the cluster service to verify the status of the storage as well as the server cluster; thus allowing the correct failover and failback decisions to be made which minimize downtime, and accelerates recovery - without human intervention. Thus the Cluster Extension software can help customers achieve 'zero' RPO and RTO in minutes or seconds.

What's New

Support for P9000 arrays Support for Microsoft Windows Server 2008 R2, Hyper-V Support for Hyper-V Live Migration Support for native clusters on RedHat and SuSe Linux

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North America Version 1 September 27, 2010

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Features and Benefits

Benefits

Disaster tolerant solutions to ensure business continuance and company survival Fully automated failover and failback Accelerated application recovery with minimum transaction loss Creation of disaster tolerant copies of your "critical business data"

Product Features

Protection against transaction data loss Because the application cluster is extended over two sites and the storage is replicated at the second site using synchronous replication methodology, data exists ubiquitously with virtually no difference in the data storage from site A to site B. No-single-point-of-failure solution to increase the availability of company and customer data Determined by the distance and latency requirements for the Continuous Access Software and cluster server. Automated failover and failback reduces the complexity involved in a disaster recovery situation. It is protection against the risk of downtime, whether planned or unplanned. Disks on the Server on both the primary and secondary sites are recognized during the initial system boot in a CLX EVA environment; therefore LUN presentation and LUN mapping changes are not necessary during failover or failback - for a truly hand-free disaster tolerant solution.
Metropolitan distance support Fully Automatic Failover and Failback No server reboot
No Single Point of failure Supreme redundancy: identical configuration of established SAN infrastructure redundancies are implemented on site B. Synchronous mode Support Continuous Access software offers synchronous data transfer mode between arrays and host. Synchronous data transfers offer the highest levels of data protection. With synchronous operations, both the source and destination copies are identical and concurrent at all times. Synchronous mirroring ensures that data copies are identical, to prevent critical data loss in the event of a failure or disaster. In this mode, data is written simultaneously to the mirrored cache of the local storage system and the remote storage system, in real time, before the application I/O is completed, thus ensuring the highest possible data consistency. Synchronous replication is appropriate when exact consistency is critical to the business application. Electronic software is now available in most countries. HP recommends purchasing electronic products over physical products when available for faster delivery and the convenience of not having to manageeither file away or throw away-confidential paper licenses. For more information, please contact an HP representative.
Electronic Software Delivery

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Software & Hardware Prerequisites
Cluster Extension Software Support
Arrays: EVA Arrays http://h20272.www2.hp.com/Pages/spock2Html.aspx?htmlFile=sw_array_eva.html Arrays: XP Arrays http://h20272.www2.hp.com/Pages/spock2Html.aspx?htmlFile=sw_array_xp.html Geo-cluster certification Windows: HP StorageWorks Cluster Extension Software is Microsoft certified. Please consult the Windows Server Catalog for the Cluster Extension Listings. Linux: Linux does not offer certification testing.

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Ordering Information
Product Description Part Number EVA arrays HP StorageWorks Cluster Extension EVA for Windows LTU T3667A HP StorageWorks EVA Cluster Extension Software for Windows e-LTU T3667AAE HP StorageWorks Cluster Extension EVA for Linux LTU T4393B HP StorageWorks EVA Cluster Extension Software for Linux e-LTU T4393BAE XP arrays HP StorageWorks Cluster Extension XP Software Windows LTU T1656A HP StorageWorks XP Cluster Extension Software Linux LTU T1657B P9000 arrays HP StorageWorks P9000 Cluster Extension Software Windows LTU TB534A HP StorageWorks P9000 Cluster Extension Software Linux LTU TB535A HP StorageWorks Cluster Extension is licensed per single server. One license is required for each node of the cluster that will contain CLX resources*, intended for failover and failback in the event of failure. A license is not required for the Quorum server (assuming that the CLX Resource is not installed on the Quorum server) and cluster nodes that do not have the CLX resource installed. NOTE: Electronic software is available in all countries except China and Japan. For China and Japan should order the physical equivalent * A resource is defined as the smallest unit in an application service. It describes the necessary parts to build an application service. The implementation of such resources in cluster software is vendor-specific. Some vendors do not allow accessing the chains between dependent resources. Microsoft Cluster Service: resource group; SG-LX (Serviceguard): package; VCS: service group.

Related Products

The following products are related to the proper operation of the EVA array. Please see product-specific QuickSpecs (attainable via the links indicated) regarding configuration and ordering information. EVA Models are modular, scalable, no-single-point-of-failure storage solutions with disaster tolerance StorageWorks EVA and business continuance support for storage consolidation on heterogeneous SANs. Ideal for enterprise-wide deployment and mission-critical applications, these solutions are the most extensible, resilient, and controllable storage solutions available. They offer maximum scalability, industry-leading performance, a fully integrated suite of centralized management tools, and unmatched data protection and disaster tolerant features. Visit the following URL for product configuration and ordering information for the new HP StorageWorks 4000/6000/8000 Enterprise Virtual Arrays: http://www.hp.com/go/eva or http://h18006.www1.hp.com/storage/arraysystems.html for general storage array product configuration and ordering information.

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Continuous Access EVA
HP StorageWorks Continuous Access EVA is a configuration prerequisite for HP Cluster Extension implementation. Continuous Access EVA is a controller-based application that performs real-time replication between HP StorageWorks Enterprise Virtual Arrays and provides customers with the highest level of storage data protection capabilities to meet their business continuity implementation goals. Customers can achieve a competitive advantage by combining disaster-tolerant solutions and disastertolerant managed services into their planning and daily routines, ensuring the data's security, availability and integrity. Continuous Access EVA is sold by utilized capacity. Please see the product URL for ordering information and part numbers: http://h18006.www1.hp.com/storage/software.html

XP Continuous Access

HP StorageWorks XP Continuous Access is a controller-based application that performs real-time replication between HP StorageWorks XP Disk Arrays. XP Continuous Access provides customers with the highest level of storage data protection capabilities to meet their business continuity implementation goals. Customers can achieve a competitive advantage by combining disaster-tolerant solutions and disaster-tolerant managed services into their planning and daily routines, ensuring the data's security, availability and integrity. XP Continuous Access is an irreplaceable component for protecting any business, yours especially. XP Continuous Access is sold by utilized capacity. Please see the product URL for ordering information and part numbers: http://h18006.www1.hp.com/storage/software.html XP Continuous Access Synchronous offers data transfer mode between arrays and host. Synchronous data transfers offer the highest levels of data protection. With synchronous operations, both the source and destination copies are identical and concurrent at all times. Synchronous mirroring ensures that data copies are identical, to prevent critical data loss in the event of a failure or disaster. In this mode, data is written simultaneously to the mirrored cache of the local storage system and the remote storage system, in real time, before the application I/O is completed, thus ensuring the highest possible data consistency. Synchronous replication is appropriate when exact consistency is critical to the business application. XP Continuous Access Asynchronous offers data transfers between storage arrays with up to 100ms oneway latency between gateways. The advantage of asynchronous replication is that the host to storage I/O is not impacted by the latency between gateways, resulting in faster write completion back to the host. Un-transmitted write I/O's are stored in the primary array cache and transmitted in bulk to the remote array. The array maintain write order using sequence numbers for each write I/O and will always have consistent data on the remote array, even if some transactions were lost during the disaster. This may be beneficial or preferred by long distance remote replication configurations. XP Continuous Access Journal improves the async replication method, by storing un-transmitted write I/O in a disk based journal device instead of the array cache, releasing valuable resource to other operations in the array. The use of Journal device provide better protection during short link failures and can maintain journal operations during High I/O load to the primary array. Write order is maintained by using sequence numbers for each write I/O and data consistency is always guaranteed on the remote array. Implementing Synchronous, Asynchronous or Journal replication is dependent on the specific replication environments and the customer requirements. Replication method can be assigned at the DR group level, and using a mixture of replication methods in the same environment is allowed.

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Additional information online http://www.hp.com http://www.hp.com/products1/storage/index.html http://www.hp.com/hps/ http://welcome.hp.com/country/us/en/prodserv.html http://welcome.hp.com/country/us/en/solutions.html http://www.hp.com/go/recovery
HP home page StorageWorks products home page HP StorageWorks products home page HP Services home page HP Products & Services home page HP Solutions Business Continuity Consulting Services

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Software Product Services
Service and Support, HP Care Pack, and Warranty Information
Data Replication Solution The Data Replication Solution Service is the most appropriate service to get a data replication solution, local and/or remote in homogeneous and heterogeneous environments, fully integrated and operational Service within some well defined boundaries reflecting natural limits of a fixed priced service. Requirements beyond these boundaries are going to be covered by SOW driven consulting services using this DR Solution Service as the fundamental building block for delivering more complex solutions. HP Services professionals work closely with your staff to analyze your storage system, understand your requirements, and design and deploy the optimal Data Replication solution for your business. Choose from three service levels: Level 1 offers installation and startup services for Continuous Access or Business Copy replication software or the Continuous Access Storage Appliance, including configuration checks, installation and basic configuration, and installation testing and customer orientation. Level 2 provides additional services such as Project Management, solution design, basic integration into your management environment, functional testing, and knowledge transfer. Level 3 provides all level 1 and 2 services, plus integration of your Data Replication solution into additional business applications.
Disaster Tolerant Management Service
http://h20219.www2.hp.com/services/cache/10823-0-0-225-121.html HP Disaster Tolerant Management service helps you implement effective recovery solutions based on the HP StorageWorks Continuous Access Software, a controller-based application that performs real-time Data Replication between HP StorageWorks EVAs. This complete package of tightly integrated services provides proven, low-risk disaster-tolerant solutions for even the most demanding and complex environments, with minimal disruption to your business. HP Disaster Tolerant Management service is expressly tailored to your IT and business requirements. At the outset, HP Services professionals work closely with you to understand your requirements and assess how your solution would interact with your existing infrastructure and business processes. Following solution delivery, knowledge transfer to your IT management and staff helps ensure that your team can manage issues that are specific to your business. include: Disaster Tolerant Services Package deliverables include Pre-installation planning and business needs review - to help ensure a timely, effective implementation Configuration and deployment of customized Disaster Tolerant management stations - to provide enhanced failover and continuous management and monitoring System manager and operator training - to familiarize your staff with key management issues; includes extensive training on recovery from failure conditions Review of your technical recovery plan - to help ensure alignment with your disaster-tolerant infrastructure Disaster recovery test suite design - to tailor tests for your newly integrated environment Disaster recovery rehearsal execution - to verify that your solution performs to your expectations

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Product Support
Product Support gives the customer access to HP's experienced technical support resources as well as access to HP's Information Services database for support on a variety of multi-vendor/multi-platform software products. Product support includes escalations and problem coordination with the appropriate engineering group. HP Services offer a variety of options to allow you to tailor your product service to meet the needs of your organization. Basic services on products can be uplifted from day one to ensure you receive the service you need when you need it.
Software product services
Standard software support (HP Care Pack or annual support contract) 24 x 7 is available 24 hours per day, Monday through Sunday, including holidays, and access rights to new versions, software product and documentation updates. Installation and Startup Service (software installation, configuration, startup testing and knowledge transfer). Tailored support contracts based on personalized statement of work: contact your local support center via http://www.hp.com/support/.

Software Warranty

HP warrants only that the Software media will be free of physical defects for a period of ninety (90) days from delivery.
Software Product Services Standard Services Additional Services
One year Software Support 24 x 7 (includes software technical support 24 x 7, software product and documentation updates Installation and startup services DR Solutions Service DT Managed Service Extended services beyond 1 year
The following services are offered as HP Care Pack Services at the time of product order
For additional software product services information for North American HP Care Pack services, as well as orderable part numbers, please refer to the URLs listed below: All storage services: http://www.hp.com/hps/storage/ Care Pack Priority Services: http://www.hp.com/hps/carepack/storage/cp_networked.html Software Support Care Pack Services: http://www.hp.com/hps/carepack/software/cp_storage.html Installation and Startup Service: http://www.hp.com/hps/storage/ns_replication.html

Copyright 2010 Hewlett-Packard Development Company, L.P. The information contained herein is subject to change without notice. Microsoft and Windows NT are US registered trademarks of Microsoft Corporation. The only warranties for HP products and services are set forth in the express warranty statements accompanying such products and services. Nothing herein should be construed as constituting an additional warranty. HP shall not be liable for technical or editorial errors or omissions contained herein.

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