STORAGE

Using Yosemite Backup Virtual Tape Libraries
to Accelerate Backup and Restore Operations
Virtual tape libraries combine the best of both worlds, using disk as the primary backup medium and tape for long-term archiving. Using backup software from Yosemite Technologies, IT organizations can combine the strengths of Dell PowerEdge servers and Dell PowerVault disk and tape hardware to create virtual tape libraries designed to improve the performance, reliability, flexibility, and scalability of network backup and restore operations.
BY NEIL MACLEAN, MIKE WEIMANN, JAKE SWIM, AND JIM LEE

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Backup Dell PowerVault storage Disaster recovery Storage Yosemite Technologies
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ape-based backups have commonly been used in data centers, but the problems with tape as a backup
Although tape is still preferable for long-term archiving because of its portability and off-line security, many enterprise IT organizations are finding that a combination of the two technologies helps provide excellent, costeffective data protection (see Figure 1). Yosemite Backup storage software can be used in conjunction with Dell disk and tape hardware to create such hybrid backup environments.
medium are well known: spotty reliability, high operational costs, and slow performance. For example, typical problems that plague tape-based backups include medium or cartridge failure during backups or restores; unreported failures or incomplete backups; misplaced or mislabeled media; long backup windows and verifications; and slow serial access times. Meanwhile, the cost of disk-based storage has dramatically decreased, and in many scenarios backing up and restoring data to and from hard disks can be achieved at a much faster rate than possible with tape technologies, enabling shorter backup windows with disk-based storage. Growing dissatisfaction with traditional tape-based backups, combined with the viability of disk as the primary target for backups, has made disk-based backups a popular data protection strategy.
www.dell.com/powersolutions
Enterprise-class performance for backups and restores
Disk-based backups can address some of the problems of tape-based data storage, but they can still leave critical data at risk. However, a disk-based backup can be effective when implemented in a multi-tiered storage hierarchyfor example, a disk-to-disk-to-tape (D2D2T) backup architecture with an automated tape loader or library. When implemented with tape and disk hardware,

DELL POWER SOLUTIONS

Reprinted from Dell Power Solutions, May 2006. Copyright 2006 Dell Inc. All rights reserved.
Feature Administration Efficiency Expense Flexibility Performance Portability Reliability Scalability
Tape Good Good Best Good Good Best Good Good
Disk Best Better Better Better Best Good Better Better
Disk and tape Better Best Good Best Better Better Best Best
disk, tape, or optical disc) using predefined criteria, such as the VTL reaching a capacity limit or an established time schedule. D2D2Ne provides the flexibility to create multiple storage hierarchies that can consist of other virtual libraries. Data can be moved to other disk systems, and from there to tape for off-site archiving. Because Yosemite Backup is designed to provide true disk-to-disk-toany functionality, it is not restricted to a rigid D2D2T configuration. In addition, all data is tracked through the Yosemite Backup catalog, freeing backup administrators from manually copying data to tape or keeping track of where data is going. D2D2Ne is designed to maximize the capabilities of the storage infrastructure cost-effectively, enabling administrators to create VTLs from underutilized disk capacity in similar or heterogeneous environments. The storage folders that are created for use by D2D2Ne can be spread across any combination of storage and on any supported platform. As a result, storage can be pooled from Novell NetWare, Linux, and Microsoft Windows environments to create the VTL. Yosemite Backup does not restrict IT environments to one platform, nor does it require proprietary hardware or additional third-party software to function as a VTL. In addition, Yosemite Backup software can be managed from a central console and is designed to restore data from any target medium in the hierarchy without staging to a VTL first. As a result, Yosemite Backups integrated VTL approach is designed to provide numerous advantages over traditional disk-only or tape-only backups, including the following benefits:

Figure 1. Comparison of typical backup and recovery media
Yosemite Backup software offers several features to enhance enterprise data storage.
Virtual tape libraries and Disk-to-Disk-to-Any option
One promising technology that is quickly gaining acceptance is the virtual tape library (VTL). This technology employs a disk array that functions as a virtual tape device or library, emulating the key characteristics of tape backup while providing the benefits and convenience of disk backup. External VTL appliances typically rely on proprietary hardware and software
Yosemite Backup software embeds the VTL function as an integrated feature, thereby providing the benefits of an external VTL appliance while avoiding drawbacks inherent in proprietary VTL technology.
to implement the VTL function, which can increase costs and, in some cases, limit scalability. In contrast, Yosemite Backup software embeds the VTL function as an integrated feature, thereby providing the benefits of an external VTL appliance while avoiding drawbacks inherent in proprietary VTL technology. The disk-to-disk technology in Yosemite Backup software offers the flexibility of two levels of disk-based backup architecture. The first level is disk-to-disk backup, in which
A single, simple console for operation and administration Fast and highly reliable backups and restores with multiple drives or volumes

Restore bypassing VTL

Source disk

Target disk (VTL)

CD, DVD, CD-RW

Backup and restore

Policy-based move/copy
VTL Windows Linux NetWare
the backup process uses designated disk volumes as the backup targetoffering the performance, reliability, and easy scalability of disk-based backups. The second level is Yosemite Backups Diskto-Disk-to-Any (D2D2Ne) option. D2D2Ne allows for true management of data through a hierarchy of storage devices (see Figure 2). For example, a backup is performed from the source disk to a target disk (configured as a VTL). D2D2Ne then manages the movement of the data from the secondary disk to tertiary storage (magnetic

Primary storage

Windows

NetWare

Secondary storage

Tertiary storage

Figure 2. Hierarchy of storage devices allowed by the Yosemite Backup Disk-to-Diskto-Any option

May 2006

Backup devices Master server Client server Media server
administrators can restore a single file or even a particular version of a single file, rather than a complete disk imageenabling fast, simple data restores that require minimal administrative time.

Network

Dell hardware and Yosemite Backup: Multi-tiered storage architecture
Dell PowerVault and PowerEdge hardware enable enterprise IT organizations to easily add disk-based backup capabilities to their existing backup infrastructures. When combined with Yosemite Backup softwares integrated VTL and D2D2Ne option, Dell hardware can be implemented in a plug-and-play manner to minimize the disruption to existing backup operations. For example, consider an enterprise scenario in which an IT organization must back up data from eight servers and 130 client PCs. Microsoft SQL Server database software and Microsoft Exchange run on two of the eight servers. Data from all the servers and clients is backed up to a Dell PowerVault 122T DLT VS80 autoloader, which provides up to eight media slots (see Figure 4). A full backup is performed every Friday, and incremental backups are performed Saturday through Thursday. One months worth of backups is stored at any given time. Data changes by about 20 percent each day. The backup window is eight hours, but the IT organization has difficulty backing up approximately 400 GB of data within this timeframe. To resolve this problem, the IT organization in this scenario could upgrade the tape devices from digital linear tape (DLT) to Ultrium 3 Linear Tape-Open (LTO-3) technology. Such an upgrade would increase the backup speed because LTO-3 has a specified backup rate of 288 GB/hour compared to the specified backup rate of approximately 10.8 GB/hour for DLT VS80. However, the LTO-3 enhancement still would not overcome issues inherent in tape-only environments such as inefficiency, inflexibility, and limited scalability. To help overcome such limitations, the organization could implement Dell disk hardware, configuring the environment for D2D2T backups. For instance, a Dell Storage Server (PowerEdge 830)
Figure 3. Intelligent data streams created by Yosemite Backup Self-Tuning Logic
Simultaneous backup and restore operations Utilization and pooling of storage from multiple, heterogeneous systems Direct restores to the point of origin from any targetmagnetic disk, tape, or optical disc Spill-over pools that allow heterogeneous servers to utilize disk volumes and thereby help ensure that backups complete successfully by not running out of disk space

Creation of multiple backup hierarchies, such as D2D2D2T and D2D2D2O Management of multiple copies of the same backup on different media Ability to maintain established tape-based policies and processes, including rotation-type backup schedules
Self-Tuning Logic technology
The primary advantage of a disk-based backup is its potential to dramatically reduce the backup window. Yosemite Backup software maximizes this advantage by offering intelligent data streaming, which helps minimize the impact of backups on systems. The Self-Tuning Logic technology included in Yosemite Backup is designed to create an unlimited number of data streams to and from the backup source and target system for fast backup and restore operations (see Figure 3). Self-Tuning Logic is designed to automatically configure the backup streams by detecting how the backup sources are configured, helping provide optimal performance. For example, if a physical disk is configured as multiple logical volumes, Self-Tuning Logic detects this configuration and sets up the backup appropriately.
Client PC 1 Client PC 130

Flexible, fast restores

In tape-based backup environments, storage software tools often require a restore from tape to a secondary disk and then back to the primary disk, effectively staging the data administrators wish to restore and increasing the restore time. In contrast, Yosemite Backup gives administrators the option of restoring directly from any backup target (magnetic disk, tape, or optical disc) if available on that medium. Restore performance can be as important as backup performance. Because Yosemite Backup tracks all data in a central catalog,
Server 1 Server 8 Backup server

SCSI connection

Dell PowerVault 122T
Figure 4. Example storage infrastructure configured for tape-only backups
running Microsoft Windows Storage Server 2003 Release 2 (R2) can provide a network attached storage (NAS) platform. In this scenario, the Dell Storage Server can act as both the Yosemite Backup application server and the disk storage platform, using Yosemite Backup softwares integrated VTL to drive the D2D2T operation. Advantages of this implementation include the following:
Client PC 1 Client PC 130 Dell PowerVault MD1000
A backup server is not required when the Yosemite Backup VTL is integrated with the Dell Storage Server. Backups and restores can be completed more quickly and more reliably than possible with tape-only backups. Restores can occur directly from tape or disk back to the point of origin. The Yosemite Backup VTL can utilize available disk capacity from Windows, Linux, and NetWare servers, providing heterogeneous spill-over capability.

Server 1

Server 8
SAS SCSI Dell PowerVault 124T
Figure 6. Example storage infrastructure configured to scale flexibly for additional disk capacity
autoloader provides up to 16 media slots and either an LTO-2-L drive or an LTO-3 drive, which are designed to achieve a native backup rate of 86.4 GB/hour or 288 GB/hour, respectively. This configuration enables disk-to-disk and disk-to-tape backups to complete well within the eight-hour backup window.
Concurrent backups and restores can take place using the Yosemite Backup VTL architecture, allowing for multiple virtual drives. Figure 5 shows the architecture for the example scenario with
the Dell Storage Server added for D2D2T backups. This configuration allows the IT organization to keep the existing tape hardware while helping to improve backup and restore performance. Cost for the added hardware can be offset by enhanced scalability, performance, reliability, and availability. For further scalability, a Dell PowerVault MD1000 system can be added (see Figure 6). This Serial Attached SCSI (SAS)/Serial ATA (SATA) device is attached behind the Dell server and is designed to provide up to 3.75 TB of additional raw disk storage capacity when fully populated with fifteen 250 GB SATA II hard disk drives. Furthermore, up to two more PowerVault MD1000 systems can be attached for up to 11.25 TB of additional raw disk storage. The PowerVault 122T tape autoloader also can be replaced with the PowerVault 124T tape autoloader to provide a capacity and performance boost in the Figure 4, 5, and 6 scenarios. This tape
Enhanced storage performance and reliability
Enterprise IT organizations can significantly enhance backup and recovery performance by migrating to D2D2T configurations such as those provided by Yosemite Backup software and Dell PowerEdge and PowerVault disk and tape systems. IT organizations can help reduce costs by integrating a disk system as a VTLfor example, deploying a Dell Storage Server to serve as a VTL can cost less than upgrading existing tape autoloaders and media. This savings can allow IT organizations to take advantage of investments in existing hardware and media while gaining the improvements in performance, reliability, scalability, and flexibility provided by disk-based backups.
Neil MacLean is a storage architect within the Office of the CTO at Dell. Mike Weimann is a Dell global account manager at Yosemite Technologies.

Jake Swim is a Dell sales engineer at Yosemite Technologies. Jim Lee is director of marketing at Yosemite Technologies.
Server 1 Server 8 Dell Storage Server (PowerEdge 830)

F OR M ORE INF ORM ATION

Dell storage: www.dell.com/storage Dell and Yosemite: www.dell.com/yosemite
Figure 5. Example storage infrastructure configured for D2D2T backups

The Bowline and Yosemite Backup
The Bowline is the most versatile knot in rope rescue. Although not quite as strong as the Figure Eight On A Bight the Bowline is a strong anchor knot (Keep in mind that the difference in strength between these two knots will not effect the overall efficiency of a rescue system). The Bowline does have an advantage in that it is a substantially easier to untie. In addition, when tying the same size loop, the Bowline is about the overall size of a Figure Eight on a Bight. This is a very important consideration when space counts, i.e. under a confined space tri-pod. The Bowline is strong under tension, and susceptible to self untying when in a relaxed position. Because of this the Bowline must be backed up with another knot. Several teams back their bowlines up with a single overhand. A single overhand is not recommended for this purpose because a nontensioned single overhand in itself is capable of untying. A double overhand stopper is a good alternative. The Bowline with a Yosemite Backup
Pat Rhodes Lead Instructor Ropes That Rescue
The Bowline with a Double Overhand Back-Up