V11 SP8

Creating a Global Deduplication Policy

The global deduplication policy enables deduplication across multiple storage policies that use a common set of disk libraries and deduplication database (DDB).

You can create a global deduplication policy by using the Create a Global Deduplication Policy wizard.

Alternatively, you can automate the creation of a global deduplication policy by using the sp_creation.xml configuration file. For more information, see Creating a Global Deduplication Policy.

Before You Begin

Before creating a global deduplication policy, follow these guidelines:

  • Associate the client computers only.
  • Define the retention rules on the individual storage policies that are associated with the global deduplication policy.


  1. From the CommCell Browser, expand Policies.
  2. Right-click Storage Policies, and then click New Global Deduplication Policy.

    A Create Global Deduplication Policy Wizard opens.

    Refer to the following sections during the global deduplication policy creation.

    Expand All

    Global Deduplication Policy Name

    Name of the global deduplication storage policy.

    For example: GDSP_for_NJDataCenter.

    Library details

    Name of the disk library.

    The initial library for the global deduplication policy. You can add more libraries as a data path after the global deduplication policy is configured.

    MediaAgent details

    Name of the MediaAgent that has access to the library. You can add more MediaAgents after the global deduplication policy is configured.

    Deduplication Modes

    Default: source-side on primary copy.

    You can accept the defaults or you can configure the Partitioned Deduplication Database (DDB) to host the DDB on multiple MediaAgents. For more information on Partitioned DDB, see Deduplication Database.

    Note: You can enable deduplication only during the storage policy creation.

    Location to host the Deduplication Database

    • DDB Location: The MediaAgent and location to host the DDB.
      • Before hosting the DDB, ensure that the MediaAgent and disk meets the hardware and software requirements referenced in Deduplication Building Block Guide.
      • Single or partitioned DDB configuration:
        • Place the DDB in a folder on a different volume or partition than that of the root file system.
        • Do not host the DDB under the software installation directory, for example software_installation_directory\Base directory.
        • For Linux, host the DDB on LVM volumes. The DDB Backups use LVM software for snapshots.
      • Partitioned DDB configuration:
        • Host each DDB on different physical drives for better performance.
        • When hosting the DDB on different MediaAgents, ensure that all MediaAgents are of similar operating system type with 64-bit version, and the MediaAgents are online.

          For more information on supported platforms, see Deduplication Building Block Guide.

        • For DDB Network Interface - By default, no data network interface pair is configured.

          We recommend that you configure a dedicated Network Interface Card (NIC) on each partition MediaAgent and set up data interface pair (DIP) between the data path and partition MediaAgents:

          • To increase the speed of the communication between the MediaAgents
          • To improve data protection job throughput
          • To avoid network bottlenecks

          If you have a NIC configured on a partition MediaAgent, specify the network interface name or IP address for the DDB Network Interface.


          • Push the firewall configuration on the DDB MediaAgent after adding a data interface pair and creating a storage policy copy. For more information, see Data Interface Pairs - Overview.
          • If DIP is configured between two MediaAgents and if no interface pair is specified during storage policy creation, the existing DIP is used between two MediaAgents.
          • No more than one DIP should be created between two clients. If another interface is created, the clients will use only the newer defined interface pair.
      • Disk configuration for the DDB LUN:
        • Format the Disk LUN that will host the DDB to a block size of 4 KB.
        • Configure LUNs so that no more than one DDB is configured on any one RAID group.
        • Configure only two DDBs per MediaAgent with two different LUN groups.
    • VSS COW volume: VSS Copy-on-Write (COW) volume is the location that hosts the snapshot of the drive where the DDB is hosted.

      By default, during DDB backups, the snapshot of the DDB drive is created by the using VSS COW method in the system default location. That is, the snapshot is stored in the DDB location.

      You can change the location that hosts the snapshot to a different location or drive for better performance on the DDB.


      • The VSS COW volume box is available only when no DDB subclient exists on a selected DDB MediaAgent and for version 11 MediaAgents.
      • If you changed the Windows shadow copy storage association to a different drive, the snapshot created during DDB backup is stored on that drive.
      • If you want to change the VSS COW volume location after storage policy creation, you can modify it on the DDB subclient. For more information, see Modifying the Properties of the Deduplication Database Subclient.
  3. Click Finish to create the global deduplication policy.

    The new global deduplication policy appears under the Storage Policies node. Additionally, a storage policy associated with the global deduplication policy is created and appears under the Storage Policies node with the Policy as name suffix.

What to Do Next

After creating a global deduplication policy, you can create a storage policy or a storage policy copy and assign it to a global deduplication policy. For information about how to create a global deduplication policy or a storage policy copy, see Creating a Storage Policy with Global Deduplication or Creating a Storage Policy Copy with Global Deduplication.