Best practices for Backup Exec 2010 R3 Deduplication Option


Best practices for Backup Exec 2010 R3 Deduplication Option

Best practices include tips and recommendations to help you effectively use the Backup Exec Deduplication Option. For more information about the Deduplication Option, see the Backup Exec 2010 Administrator's Guide.


Symantec strongly recommends that you upgrade to Backup Exec 2010 R3. The R3 version contains many enhancements for deduplication.

The following best practices apply to deduplication storage folders:

  • Use a dedicated volume for a deduplication storage folder.

  • Ensure that the volume you use for a deduplication storage folder has enough space to hold data from multiple servers. Symantec recommends that you use a dynamic volume that can grow as needed.

  • Ensure that the media server on which you create a deduplication storage folder has the appropriate amount of RAM. The minimum amount of RAM is 8 GB, which supports up to 5 TB of deduplicated data.


    This minimum requirement is in addition to the minimum requirements for Backup Exec.

    For more than 5 TB of data, use the following calculation to determine the required amount of RAM:

    1.5 GB x N, where N equals the number of TB of storage in the deduplicated volume. Up to 32 TB of data is supported.

    Example: Use the following equation to calculate the required amount of RAM for 10 TB of data:

    1.5 x 10 = 15 GB RAM

  • Symantec recommends the following as minimum disk speeds per individual read, write, or verify operation for 32 TBs of storage:

    • 130 MB per second
    • 200 MB per second for enterprise-level performance

The above recommendations are for the performance of a single operation. You may need more capability depending on your objectives for writing to and reading from disk.

Note: You should be aware of the effects that computer disk speeds have on deduplication performance.

Computer disk speeds can have the following effects on deduplication performance:

  • Computers with disk speeds greater than 200 MB per second have optimal read and write performance deduplication.
  • Computers with disk speeds between 150-200 MB per second have sufficient read and write speed for deduplication.
  • Computers with disk speeds between 100-150 MB per second have some operations with degraded performance.
  • Computers with disk speeds less than 100 MB per second experience poor performance. You should improve disk reads and writes before you install and run deduplication.


  • For deduplication disk storage connection, the following are supported:
    • Storage area network (Fibre Channel or iSCSI)
    • Direct-attached storage (DAS)
    • IInternal disks
  • For deduplication disk storage connection, the following are not supported:
    • Removable disks including USB
    • eSATA
    • FireWire devices
  • The media server should have redundant connectivity to the storage.
  • The storage network must be a dedicated, low latency network with a maximum of 1-millisecond latency per round trip.
  • The storage network must have enough bandwidth to meet your throughput objectives. Symantec supports the following storage network bandwidths:
    • iSCSI SANs with a bandwidth of at least 10 Gb per second.
    • Fibre Channel SANs with a bandwidth of at least 4 Gb per second.
  • Symantec requires a minimum bandwidth of 130 MB per second for read and write performance. Bandwidth that is less than 130 MB per second may be used in smaller, less resource-intensive environments. However, as usage increases, deduplication requires more bandwidth to ensure adequate throughput for deduplication processes and backups. Otherwise, performance and stability are negatively affected.

  • Perform regular backups of the deduplication storage folder to removable media. Create this job separately from the backup job that you use to protect the rest of your system. In the backup selection list, the Backup Exec Deduplication Storage node is located under the User Data node under Shadow Copy Components.Use a dedicated logon account when creating a deduplication storage folder.

  • Use the spauser.exe utility if you have to change the password for the Backup Exec logon account that you specified when you created a deduplication storage folder (Note that the Backup Exec logon account is specified on the General tab). When you specify a logon account for a deduplication storage folder, an additional user account is created for the deduplication components with the same user name and password. However, if you change the credentials for the Backup Exec logon account, the credentials for the additional user account are not changed automatically. You must use the spauser.exe utility to update the password for the additional user account. This account is known as the "User 1" account when you use the spauser.exe utility to view a list of user names that are associated with the deduplication storage folder. The passwords must be kept synchronized to ensure that the deduplication storage folder will be accessible after services are restarted, and to facilitate recovery of the deduplication storage folder after a system failure.

  • Exclude the deduplication storage folder from your antivirus scans. If an antivirus scanner deletes or quarantines the files from the deduplication disk storage folder, access to the deduplication disk storage folder may be disabled.

  • Do not use Backup Exec's Intelligent Disaster Recovery (IDR) to recover data from local deduplication storage folders. IDR recovery is not supported for deduplication storage folders.

  • Perform a duplicate backup job so that you have redundant backups of the data in your deduplication storage folder. This method is preferred over performing full backups using the deduplication writer because this method is easier to control.

  • Review the tech note titled "Getting the most out of the Deduplication Option and Deduplication Storage Folders" for more details about using deduplication storage folders. The tech note is available from the following link:

  • On the drive properties where the deduplication storage folder is located, ensure that the following option is not selected: Allow files on this drive to have contents indexed in addition to file properties.  To access the drive properties, in Windows Explorer, right-click the drive on which the deduplication storage folder is located. Click Properties, and then click the General tab.

  • Do not delete any files from the deduplication storage folder. To reclaim space from the deduplication disk storage device, refer to the following tech note:

The following best practices apply to verify jobs:

  • Verify all backup data.

  • Use a verify template in a policy after each backup job and duplicate job. This applies if you have used a deduplication storage folder for the backup job.


    Due to the rehydration of data during the verify process, slow performance over Wide Area Networks (WAN) can be expected if you use optimized duplication and verify templates.

  • Disable the option Allow this job to have direct access to this device if you use client-side deduplication with a verify template.

The following best practices apply to using deduplication with SQL:

  • Set the option Use Advanced Open File Option as a backup job property for the SQL backup job. This option allows data to be deduplicated in the most effective way.

  • Use Microsoft SQL Server Management Studio to restrict SQL's use of physical memory. This option can be set for each SQL instance by selecting Properties > Memory. Restricting SQL to use 85% to 90% of total physical memory can prevent a situation in which backup rates may be reduced to 10% of the expected rate due to memory restrictions.

The following best practices help you to use the Deduplication Option effectively:

  • Use client-side deduplication for all deduplication jobs, except in the following situations:

    • You are backing up a non-Windows platform, such as NetWare, or NAS servers (NetApp, EMC, etc.).

      Note: Client-side deduplication is available for some Linux versions. You can find a list of supported Linux versions in the Backup Exec Software Compatibility List:

            Software Compatibility List

    • The remote computer has limited or no resources available to dedicate to the deduplication process during backup jobs.

    • You want to back up multiple servers in the same job.

    • Your environment contains multi-server configurations of Microsoft SharePoint servers, Microsoft Exchange 2010 DAG servers, and Symantec Enterprise Vault servers.

    • You want to back up virtual machines with the Agent for VMware Virtual Infrastructure.

  • Ensure that the appropriate third-party vendor plug-in is installed for an OpenStorage Technology (OST) device and exists in the Backup Exec directory. The plug-in enables Backup Exec to detect the OST device and display the device in the server list.

  • Inventory and catalog the media when you restore from an optimized duplication backup.

  • Do not create duplicate backup jobs across the WAN for backup sets that have Granular Recovery Technology (GRT) enabled.

  • Disable RAID caching on the disk where the deduplication storage folder is located.

  • Apply the following Microsoft hotfixes to improve performance:


Terms of use for this information are found in Legal Notices.



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