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Tanmoy1
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14 years ago
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What is SCSI Persistance Reserve in Netbackup

What is SCSI Persistance Reserve in Netbackup and what is the advantage of this in Netbackup environment.Please guide me smiley

  • Have you had a look at the Admin Guides yet?

    Extract from Administrator's Guide for Windows I  http://www.symantec.com/docs/TECH127079 :

    p. 156:
    The SCSIpersistentreserve option provides SCSI persistent reserve protection
    for SCSI devices. The devices must conform to the SCSI Primary Commands -
    3 (SPC-3) standard. SCSI persistent reserve is valid for NetBackup 6.5 and later
    servers only. If you enable SCSI persistent reserve, NetBackup does not send
    persistent reserve commands to NetBackup media servers earlier than release
    6.5.

    Note: Ensure that all of your hardware processes SCSI persistent reserve commands
    correctly. All of your hardware includes Fibre Channel bridges. If the hardware
    does not process SCSI persistent reserve commands correctly and NetBackup is
    configured to use SCSI persistent reserve, no protection may exist.

    p. 159:
    Recommended use for Enable SCSI reserve property

    All tape drive and bridge vendors support the SPC-2 SCSI reserve and release
    method. NetBackup has used SPC-2 SCSI reserve since NetBackup 3.4.3, and it is
    the default tape drive reservation method in NetBackup. SPC-2 SCSI reserve is
    effective for most NetBackup environments.
    The SCSI persistent reserve method may be more effective in the following
    environments because it provides device status detection and correction:
    ■ NetBackup media servers operate in a cluster environment.
    NetBackup can recover and use a reserved drive after a failover (if NetBackup
    owns the reservation). (With SPC-2 SCSI reserve, the drive must usually be
    reset because the reservation owner is inoperative.)
    ■ The drive must have high availability.
    NetBackup can resolve NetBackup drive reservation conflicts and maintain
    high drive availability. (SPC-2 SCSI reserve provides no method for drive status
    detection.)
    However, the SCSI persistent reserve method is not supported or not supported
    correctly by all device vendors. Therefore, thoroughly analyze the environment
    to ensure that all of the hardware supports SCSI persistent reserve correctly.
    Symantec recommends careful consideration of all of the following factors before
    Enable SCSI reserve is used:
    ■ Only a limited number of tape drive vendors support SCSI persistent reserve.
    ■ SCSI persistent reserve is not supported or not supported correctly by all fibre
    channel bridge vendors. Incorrect support in a bridge means no access
    protection. Therefore, if the environment uses bridges, do not use SCSI
    persistent reserve.
    ■ If parallel SCSI buses are used, carefully consider the use of SCSI persistent
    reserve. Usually, parallel drives are not shared, so SCSI persistent reserve
    protection is not required. Also, parallel drives are usually on a bridge, and
    bridges do not support SCSI persistent reserve correctly. Therefore, if the
    environment uses parallel SCSI buses, do not use SCSI persistent reserve.
    ■ The operating system tape drivers may require extensive configuration to use
    SCSI persistent reserve. For example, if the tape drives do not support SPC-3
    Compatible Reservation Handling (CRH), ensure that the operating system
    does not issue SPC-2 reserve and release commands.
    If any of the hardware does not support SCSI persistent reserve, Symantec
    recommends that SCSI persistent reserve is not used.


     

  • Have you had a look at the Admin Guides yet?

    Extract from Administrator's Guide for Windows I  http://www.symantec.com/docs/TECH127079 :

    p. 156:
    The SCSIpersistentreserve option provides SCSI persistent reserve protection
    for SCSI devices. The devices must conform to the SCSI Primary Commands -
    3 (SPC-3) standard. SCSI persistent reserve is valid for NetBackup 6.5 and later
    servers only. If you enable SCSI persistent reserve, NetBackup does not send
    persistent reserve commands to NetBackup media servers earlier than release
    6.5.

    Note: Ensure that all of your hardware processes SCSI persistent reserve commands
    correctly. All of your hardware includes Fibre Channel bridges. If the hardware
    does not process SCSI persistent reserve commands correctly and NetBackup is
    configured to use SCSI persistent reserve, no protection may exist.

    p. 159:
    Recommended use for Enable SCSI reserve property

    All tape drive and bridge vendors support the SPC-2 SCSI reserve and release
    method. NetBackup has used SPC-2 SCSI reserve since NetBackup 3.4.3, and it is
    the default tape drive reservation method in NetBackup. SPC-2 SCSI reserve is
    effective for most NetBackup environments.
    The SCSI persistent reserve method may be more effective in the following
    environments because it provides device status detection and correction:
    ■ NetBackup media servers operate in a cluster environment.
    NetBackup can recover and use a reserved drive after a failover (if NetBackup
    owns the reservation). (With SPC-2 SCSI reserve, the drive must usually be
    reset because the reservation owner is inoperative.)
    ■ The drive must have high availability.
    NetBackup can resolve NetBackup drive reservation conflicts and maintain
    high drive availability. (SPC-2 SCSI reserve provides no method for drive status
    detection.)
    However, the SCSI persistent reserve method is not supported or not supported
    correctly by all device vendors. Therefore, thoroughly analyze the environment
    to ensure that all of the hardware supports SCSI persistent reserve correctly.
    Symantec recommends careful consideration of all of the following factors before
    Enable SCSI reserve is used:
    ■ Only a limited number of tape drive vendors support SCSI persistent reserve.
    ■ SCSI persistent reserve is not supported or not supported correctly by all fibre
    channel bridge vendors. Incorrect support in a bridge means no access
    protection. Therefore, if the environment uses bridges, do not use SCSI
    persistent reserve.
    ■ If parallel SCSI buses are used, carefully consider the use of SCSI persistent
    reserve. Usually, parallel drives are not shared, so SCSI persistent reserve
    protection is not required. Also, parallel drives are usually on a bridge, and
    bridges do not support SCSI persistent reserve correctly. Therefore, if the
    environment uses parallel SCSI buses, do not use SCSI persistent reserve.
    ■ The operating system tape drivers may require extensive configuration to use
    SCSI persistent reserve. For example, if the tape drives do not support SPC-3
    Compatible Reservation Handling (CRH), ensure that the operating system
    does not issue SPC-2 reserve and release commands.
    If any of the hardware does not support SCSI persistent reserve, Symantec
    recommends that SCSI persistent reserve is not used.