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Release Preview Data Early, if Appropriate

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By releasing Preview Data earlier, system resources are freed sooner rather than later. This article addresses two configurable items that can help free resources earlier, under the right conditions:

• Backup Inactivity Timeout

  
  

• Preview Data Release Point (applies to all versions prior to 9.1 and all OFM versions for NetWare LFS)

  
  

Backup Inactivity Timeout

Set Open File Manager's Backup Inactivity Timeout variable to 20 minutes if you don't manually change tapes. This variable is located in the Open File Manager System Properties-General Tab and is set to a default of 120 minutes. The main reason for this variable is to allow a backup operator 2 hours to change tapes before Open File Manager releases the Preview Data from the Pre-Write Cache. The countdown starts when the backup stops reading files (for tape change, for example.) This keeps the backup consistent between tapes.

Open File Manager cannot determine whether the backup completed,or stopped for a tape change. The Backup Inactivity Timeout also controls how long Open File Manager manages open files AFTER backup. At the default setting, Open File Manager keeps the system synchronized and caches Preview Data for 2 hours after backup. If you don't manually change tapes, setting Backup Inactivity Timeout to 20 minutes will reduce unnecessary I/O and resource utilization outside the backup window.

In addition, administrative functions such as checking the details of a previous backup job in some backup applications (Veritas Backup Exec for NT, for example) use the same process that causes Open File Manager to synchronize and start managing open files. Setting Open File Manager's Backup Inactivity Timeout to 20 minutes will allow Open File Manager to un-synchronize earlier and not unnecessarily tie up resources outside the backup window (when you may be running other resource-intensive activities.)

Preview Data Release Point

IMPORTANT: This step applies to all versions prior to 9.1 and all OFM versions for NetWare LFS.

Set Open File Manager's Preview Data Release Point to "after backup," if you do not perform a verify after backup. Setting this Open File Manager variable in the System Properties > General tab from its default of "after verify" will release Preview Data, and the memory resources to track it, as soon as the backup application has copied the file to tape.