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Estimate how many DPM servers are required

Updated: November 1, 2013

Applies To: System Center 2012 - Data Protection Manager, System Center 2012 R2 Data Protection Manager, System Center 2012 SP1 - Data Protection Manager

The number of System Center 2012 - Data Protection Manager (DPM) servers you’ll need to deploy is based on the following factors:

  • DPM limitations

  • The workloads you want to protect

  • How often data changes on protected workloads

  • How often the data will be synchronized

  • The amount of space in the storage pool

  • Available bandwidth of each protected computer

  • Aggregate bandwidth on the DPM server

DPM limitations

DPM imposes a number of limitations that will affect your deployment, including data size limits for different workloads, and snapshot limits.

Data limits for protected workloads

The following table lists the data source limits that a DPM server that meets the minimum hardware requirements can protect and the recommended disk space required per DPM server.

 

Data source Data source limit per DPM server Recommended disk space

SQL Server

Up to 2000 databases

80 TB

Client computers

3000 client computers

Exchange Server

80 TB

SharePoint

25 TB

Snapshot limits

A DPM server can store up to 9,000 disk-based snapshots, including those retained when you stop protection of a data source. The snapshot limit applies to express full backups and file recovery points, but not to incremental synchronizations.

The snapshot limit applies per DPM server, regardless of storage pool size. When you configure protection groups, the DPM server is provisioned for the number of snapshots to accommodate the protection group configuration. You can use the following cmdlet in DPM Management Shell to identify the number of snapshots for which the server is provisioned:

$server=Connect-DPMServer Name of the DPM server

$server.CurrentShadowCopyProvision

When planning your DPM deployment, consider the snapshot limit as part of the DPM server capacity. The following table lists examples of the number of snapshots that result from different protection policies.

 

Protection policy Snapshots

Exchange storage group: daily express full backup and 15-minute incremental synchronization with a retention range of 5 days

5

Volume on a file server: 3 daily recovery points with a retention range of 21 days

63

SQL Server database: 2 express full backups daily with a retention range of 14 days

28

Total:

96

Estimating the data change rate

To get an estimate of your data change rate, you can review an incremental backup for a recent, average day. The percentage of your data included in an incremental backup is usually indicative of your data change rate. For example, if you have a total of 100 GB of data and your incremental backup is 10 GB; your data change rate is likely to be approximately 10 percent per day.

However, because the method that DPM uses to record changes to data is different from that of most backup software, incremental backup size is not always a precise indicator of data change rate. To refine your estimate of your data change rate, consider the characteristics of the data you want to protect.

For example, while most backup software records data changes at the file level, DPM records changes at the byte level. Depending on the type of data that you want to protect, this can translate to a data change rate that is lower than the incremental backup might suggest.

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For additional resources, see Information and Support for System Center 2012.

Tip: Use this query to find online documentation in the TechNet Library for System Center 2012. For instructions and examples, see Search the System Center 2012 Documentation Library.
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