Unable to assign subclients to a Storage Policy

Article ID: DD0006 Storage Policy is not accepting new subclients due to Deduplication Database (DDB) performance contraints

Symptom

You cannot assign new subclients to the storage policies that use the DDB. However, backups continue for the current subclients associated with the storage policy.

The "no entry" icon added to the Storage Policy icon in the CommCell Browser indicates the storage policy does not accept the new subclients.

The following message is displayed on the Storage Policy Properties dialog box.

This Storage Policy will not accept anymore subclient associations since Deduplication database has reached QI time threshold.

Cause

The subclient association to a storage policy is not allowed when all of the following conditions are true:

  • The Average Q&I Time across Partitions in last 14-days has reached 80% of the two millisecond threshold.
  • The Total number of Unique blocks of the DDB exceeded 200 million blocks, that is, the backend data size is approximately 20 TB or higher.
    For DDB with multiple partitions, the Total number of Unique blocks for each partition needs to exceed 200 million blocks.

The average QI time for the past 14 days is calculated as the 14-day median QI time value.

Resolution

  • Improve QI performance of the DDB. See DD0004 for more information.
  • If you must assign subclients to the same storage policy even though it has reached its threshold, you can eliminate the restriction for an additional 30 days (grace period).
    For information on eliminating the restriction of subclients association to a storage policy using XML, see Allow Subclient Association to a Storage Policy using XML.

    To allow a 30-day grace period for subclient association, complete the following steps:
    1. From the CommCell Browser, expand Policies | Storage Policies.
    2. Right-click the appropriate storage policy, and then click Properties.
    3. In the Storage Policy Properties dialog box, select the Allow subclient associations to this storage policy for 30 More Days check box.

      This option allows you to assign subclients to the storage policy for an additional 30 days.

      After 30 days, if both the average QI time is still above 80% and the total number of unique blocks is above 200 million blocks, the storage policy will not accept new subclients. You can enable this option repeatedly to continue to associate new subclients until the average QI time falls below 80% or the total number of unique blocks falls below 200 million blocks.
       
    4. Click OK.

When you reopen the Storage Policy Properties dialog box, the grace period end date is displayed in the General tab.

If you set the Allow subclient associations to this storage policy for 30 More Days option, and both the average QI time is above 80% and the total number of unique blocks is above 200 million blocks, we recommend that you relocate the DDB to a server that meets the specification referenced in the Deduplication Building Block Guide.

  • To avoid blocking the storage policy for subclient association, monitor the Event Viewer window for the following event messages:?
    • When the value for the Average Q&I time across Partition is last 3 days option reaches 70% of the threshold for the past 3-days of a DDB partition and the Total number of Unique blocks of that DDB has reached 100 million blocks (that is, the backend data size is approximately 10 TB or higher), the following event message marked with Critical severity is generated.
       
      Deduplication database(s) reaching QI time threshold for adding new Subclient [{StoreName[SIDB_SP01_Primary (Apr 2 2014 4:40PM)] StoragePolicy[SP01] Copy[Primary] MediaAgent [MediaAgent01] Path [e:\DDB01] PrimaryRecords[232790] AvgQITime[1422]}].
      Please review the deduplication database configuration. For more details please refer Deduplication Building Block Guide on Books Online.
    • When the value for the Average Q&I Time across Partitions in last 14 days option reaches 80% of the threshold for the past 14-days of a DDB partition and the Total number of Unique blocks of that DDB has reached 200 million blocks (that is, the backend data size is approximately 20 TB or higher), the following event appears.
       
      Deduplication database(s) crossed QI time threshold for adding new Subclient [{StoreName[SIDB_SP01_Primary(Apr 6 2014 2:10PM)] StoragePolicy[SP01] Copy[Primary] MediaAgent [MediaAgent01] Path [e:\DDB01] PrimaryRecords[239894] AvgQITime[3035]}].
      Please review the deduplication database configuration. For more details please refer Deduplication Building Block Guide on Books Online.