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4 replies Latest Post - ‏2012-10-12T20:53:31Z by SystemAdmin
SystemAdmin
SystemAdmin
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Pinned topic Does GPFS provide a mean to verify data integrity?

‏2012-10-10T16:13:00Z |
My customer requires a mean to ensure the integrity of data stored on disk.
Does GPFS provide a mechanism such as a checksum to verify data integrity?
Thanks
Daniel
Updated on 2012-10-12T20:53:31Z at 2012-10-12T20:53:31Z by SystemAdmin
  • SystemAdmin
    SystemAdmin
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    Re: Does GPFS provide a mean to verify data integrity?

    ‏2012-10-10T16:32:26Z  in response to SystemAdmin
    Please read about "GPFS Native RAID", which among other things, does include software checksumming of all disk blocks.
  • SystemAdmin
    SystemAdmin
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    Re: Does GPFS provide a mean to verify data integrity?

    ‏2012-10-11T08:10:20Z  in response to SystemAdmin
    Thanks, Marc.
  • osc
    osc
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    Re: Does GPFS provide a mean to verify data integrity?

    ‏2012-10-12T19:19:08Z  in response to SystemAdmin
    T10pi is also your friend. Most modern subsystems have support for it if you stick with SAS disks. Sata has some friendly features here and there like "satasure" and whatnot, but stick with Sas if you truly NEED verification on write, background verify, etc.
    • SystemAdmin
      SystemAdmin
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      Re: Does GPFS provide a mean to verify data integrity?

      ‏2012-10-12T20:53:31Z  in response to osc
      I confess that up to a few minutes ago I had no knowledge of T10PI (Scsi protection information)

      Seems that by itself, it does nothing - the filesystem or database that is doing the SCSI-writes and reads has to insert and later verify the 8 bytes per sector defined in the standard.

      When you google "T10 protection information" you'll find several write-ups - here a piece of one at

      http://www.ibm.com/developerworks/aix/library/au-T10E2E/index.html
      ... In the Type 1 implementation the 8 byte DIF consists of a Ref Tag, an App Tag, and a CRC. A Type 1 DIF is defined as a having a 2 byte CRC, a 2 byte App tag, and a 4 byte Ref tag, which consists of the lower 32 bits of the logical block address....