Adjust Timeout Value for SCSI Commands on MediaAgents

If you see devices timing out (in MediaManager.log file) and jobs failing as a result, you may want to adjust the timeout value for SCSI commands to these devices.

• On Windows, the system uses native drivers and the timeout values are determined by the drivers.

  The SCSI timeout values may only apply to the SCSI commands associated to the library. The following are the SCSI timeout registry values that are available on Windows:

  HKEY_LOCAL_MACHINE\SOFTWARE\CommVault Systems\Galaxy\Instance<xxx>\ScsiTimeouts

  INITIALIZE_ELEMENT_STATUS    *600*
  INITIALIZE_ELEMENT_STATUS_WITH_RANGE *600*
  INQUIRY    *30*
  MOVE_MEDIUM    *1500*
  READ_ELEMENT_STATUS    *600*

• On UNIX it's possible to specify timeout values for any SCSI command as long as the command is delivered using the pass-through driver as arm changers are always accessed using pass-through nodes on all UNIX platforms.

  Tape drives by default are accessed using native drivers on AIX, Solaris, HP-UX, Linux and Tru64. Native drivers do not offer a way to customize SCSI timeouts. However, it is possible to enable pass-through mechanism from the CommCell Console by disabling the Use Native device driver for data transfer for tape media option in the MediaAgent Properties.

  Once this is done pass through SCSI timeouts can be customized by modifying the following registry values:

  /etc/CommVaultRegistry/Galaxy/Instance<xxx>/ScsiTimeouts

  .internal.unique_id 1124467005_16773_40966_392845154
  DEFAULT *120*
  ERASE *18000*
  INITIALIZE_ELEMENT_STATUS *600*
  INITIALIZE_ELEMENT_STATUS_WITH_RANGE *600*
  LOAD *900*
  MOVE_MEDIUM *1500*
  READ *900*
  READ_ELEMENT_STATUS *600*
  RESERVE *1200*
  REWIND *1800*
  SEEK_BLOCK *900*
  SPACE *900*
  WRITE *900*
  WRITE_FILEMARKS *900*

These are the rules that should be observed while making the changes:

• All timeouts are in seconds.
• If a timeout is inside asterisks (e.g. *600*), it means that this is a default timeout. If you want to change the default value, you must remove the asterisks, or else the system will revert the timeout back to the default. This is done to simplify upgrades.
• If you want to change timeout for a command, which is explicitly listed in registry, you must put the new value on that respective line.
• If you want to change timeout for an unlisted command, you have two ways:
  • You can change the value for the DEFAULT timeout,
  • You can add the unlisted command by inserting a line like "CDB_XX <timeout>" where XX is the command's cdb[0] in hex.