Delayed Stubbing

By default, the stubbing process is delayed by three Disaster Recovery (DR) backups and two days after data is backed up using a full, incremental, or a synthetic full backup. This ensures that in a disaster recovery scenario you can roll back to a previous CommServe DR version without any data loss. Without delayed stubbing, when you perform a DR restore, recalls might fail for files that were backed up after a DR backup.

About this Task

  • When using synthetic full backups, note the following:
    • Synthetic full backup jobs must be run less frequently than the DR backup jobs.
    • Retention of the DR backup job must be longer than the frequency of the synthetic full backup job schedule.
    • The time interval between the synthetic full backup jobs must be greater than the maximum value of (m*x, n).

      where m and n are nMinDRBackupBeforeStubbing and nMinDaysBeforeStubbing additional setting values respectively, and x is the DR backup frequency in days.

    • Each time a synthetic full backup job is run, the count for the number of DR backups and the number of days to delay the stubbing process is reset to additional setting values. If the additional settings are not present on the CommServe computer, then the count for the number of DR backups and the number of days to delay the stubbing process is reset to the default values of three and two respectively.
  • You can modify the number of DR backups and the number of days to delay the stubbing process by configuring the nMinDRBackupBeforeStubbing and nMinDaysBeforeStubbing additional settings on the CommServe.

    • If the nMinDRBackupBeforeStubbing additional setting is not present on the CommServe, then stubbing is delayed by three DR backups.
    • If the nMinDaysBeforeStubbing additional setting is not present on the CommServe, then stubbing is delayed by two days.
    • Both the additional settings are required for delayed stubbing. To disable delayed stubbing, set the value of both additional settings to 0.

Procedure

Use the following steps to modify the number of DR backups to run before the stubbing process:

  1. From the CommCell Console, right-click the CommServe and click Properties.
  2. In the CommCell Properties dialog box, on the Additional Settings tab, click Add.
  3. In the Add Additional Settings on Windows Client dialog box, specify the number of DR backups to delay the stubbing process after a backup:
    1. In the Name box, type nMinDRBackupBeforeStubbing. The Category and Type details are automatically populated.

      Click Lookup and search for the additional setting using the Find box.

    2. In the Value box, type number_of_DR_backups_to_delay_stubbing_after_backup.
    3. Click OK.
  4. Click OK to close the CommCell Properties dialog box.

Use the following steps to modify the number of days to delay the stubbing process:

  1. From the CommCell Console, right-click the CommServe and click Properties.
  2. In the CommCell Properties dialog box, on the Additional Settings tab, click Add.
  3. In the Add Additional Settings on Windows Client dialog box, specify the number of days to delay the stubbing process after a backup:
    1. In the Name box, type nMinDaysBeforeStubbing. The Category and Type details are automatically populated.

      Click Lookup and search for the additional setting using the Find box.

    2. In the Value box, type number_of_days_to_delay_stubbing_after_backup.
    3. Click OK.
  4. Click OK to close the CommCell Properties dialog box.

Example

To delay the stubbing process for 7 DR backups and 3 days, configure the settings as follows:

  • nMinDRBackupBeforeStubbing = 7
  • nMinDaysBeforeStubbing = 3

The delayed stubbing process involves two steps:

  1. Find a DR backup that meets the requirement of 3 days, and greater than or equal to the 7th DR backup (counting from the latest DR job to the oldest DR job).
  2. Any file that is backed up before the start time of the DR backup determined in the previous step will become eligible for stubbing.