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Is it safe to use hdparm command to get or set hard disk parameters under Linux?
Posted by Vivek Gite <vivek@nixcraft.com>
hdparm command provides a command line interface to various hard disk ioctls supported by the stock Linux ATA/IDE device driver subsystem. Some options may work correctly only with the latest kernels. Getting hard disk information You can safely use hdparm to get hard disk information. For example, try out following command to get information about SCSI hard disk (login as the root user): # hdparm /dev/sda OR get detailed information: # hdparm I /dev/hda Output: /dev/hdb: ATA device, with non-removable media Model Number: SAMSUNG SP0822N Serial Number: S06QJ10Y123456 Firmware Revision: WA100-31 Standards: Used: ATA/ATAPI-6 T13 1410D revision 1 Supported: & some of 7 Configuration: Logical max current cylinders heads sectors/track -CHS current addressable sectors: 4128705 LBA user addressable sectors: 156368016 LBA48 user addressable sectors: 156368016 device size with M = 1024*1024: 76351 MBytes device size with M = 1000*1000: 80060 MBytes (80 GB) Capabilities: LBA, IORDY(can be disabled) Queue depth: 1 Standby timer values: spec'd by Standard, no device specific minimum R/W multiple sector transfer: Max = 16 Current = ? Recommended acoustic management value: 254, current value: 0 DMA: mdma0 mdma1 mdma2 udma0 udma1 *udma2 udma3 udma4 udma5 Cycle time: min=120ns recommended=120ns PIO: pio0 pio1 pio2 pio3 pio4 Cycle time: no flow control=120ns IORDY flow control=120ns Commands/features: Enabled Supported: NOP cmd * READ BUFFER cmd * WRITE BUFFER cmd * Host Protected Area feature set * Look-ahead * Write cache * Power Management feature set
Security Mode feature set SMART feature set * FLUSH CACHE EXT command * Mandatory FLUSH CACHE command * Device Configuration Overlay feature set * 48-bit Address feature set Automatic Acoustic Management feature set SET MAX security extension * DOWNLOAD MICROCODE cmd * SMART self-test * SMART error logging Security: Master password revision code = 65534 supported not enabled not locked not frozen not expired: security count supported: enhanced erase 50min for SECURITY ERASE UNIT. 50min for ENHANCED SECURITY ERASE UNIT. HW reset results: CBLID- below Vih Device num = 1 determined by the jumper Checksum: correct You can also find out how fast your hard disk can read or write (cache) data. Run following command 2-3 times to get meaningful results: # hdparm tT /dev/hda Output: /dev/hda: Timing cached reads: 1008 MB in 2.00 seconds = 502.96 MB/sec Timing buffered disk reads: 54 MB in 3.09 seconds = 17.46 MB/sec Setting hard disk parameters Setting parameter can be dangerous. Your OS/Linux kernel is optimized to autodetect the correct settings for most hard drives. Do not try to set new values using hdparm command. Wrong parameter may result into loss and/or corruption of data. Read man page of hdparm for all options. You can configure your hard disk using /etc/hdparm.conf under Debian Linux. Under RedHat Linux try /etc/sysconfig/harddisk file. Caution: Do not modify above files, leave files, as it is unless you know exactly what you are doing.
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