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Configuring fractional space reservation policies

You can enable fractional space reservation and also set the value of the fractional space reservation. With fractional reserve, the space reserved for overwrites is set to less than 100 percent of the total size of the space-reserved LUNs in a traditional volume or a flexible volume.

About this task

Note: You cannot configure fractional space reservation policies through the Database Availability Group (DAG). You can configure them only when you connect to a member server of the DAG.

Steps

  1. In the Actions pane, select Fractional Space Reservation Settings.
  2. Click the Policy Settings tab.
  3. Specify which policy you want to view or change.
    If you want to access this... Then do this...
    The default policy In the navigation tree, select Default Policy.
    A volume-specific policy In the navigation tree, select the storage system and then the volume.
  4. To enable fractional space reservation monitoring, select the Enable Fractional Space Reservation Monitoring check box.
  5. Use Automatically delete backup sets to enable or disable automatic deletion of Exchange backup Snapshot copies in fractional-space-reserved LUNs on the volume.
    If you want to... Then...
    Enable automatic deletion of Exchange backup Snapshot copies Select Delete backups that include LUNs which have less than 100% overwrite reservation, and then skip ahead to Step 8.
    Disable automatic deletion of Exchange backup Snapshot copies Clear Delete backups that include LUNs which have less than 100% overwrite reservation, and then proceed to Step 6.
  6. In the Trigger point for overwrite reserve utilization field, type the level of overwrite reserve utilization (in percentage of total reserve) that is to trigger deletion of Exchange backup Snapshot copies.

    The value must not be a negative integer that is less than the Trigger point for overwrite reserve utilization value in the Automatic dismount of databases panel.

  7. In the Number of most recent backup sets to retain field, type the number of backup sets to be retained if automatic backup set deletion is triggered.

    The value must be an integer from 1 through 256 and should be based on the backup creation and verification schedule.

  8. Use the Automatically dismount databases panel to configure automatic unmounting of Exchange databases in fraction-space-reserved LUNs on the volume.

    Note: Because automatic deletion of Exchange backup Snapshot copies does not necessarily prevent an out-of-space condition on the volume, SnapManager does not allow you to disable unmounting of databases for any fractional space reservation policy.

  9. In the Trigger point for overwrite reserve utilization field, type the level of overwrite reserve utilization (in percentage of total reserve) that is to trigger unmounting of Exchange databases.

    The value must be an integer from 0 through 99.

    Note: If Snapshot copy autodelete is enabled, SnapManager requires that this threshold be set to a higher level than the threshold that triggers automatic Snapshot copy deletion. Setting the threshold at a higher value ensures that Snapshot copy autodelete is triggered first.

  10. Click OK.
Related concepts
Fractional space reservation policies
Automatic deletion of Exchange backup copies
Related tasks
Viewing current fractional space reservation data for a LUN