Setting Up Data Co-Location

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Applies To: System Center Data Protection Manager 2007

System Center Data Protection Manager (DPM) 2007 allows you to co-locate protection groups on a tape. Using this feature, you can group recovery points of multiple protection groups on a single tape. This optimizes tape usage in case you have many small protection groups.

Co-Locating Data on a Tape

To use data co-location on DPM 2007, you must download and install KB 949779, which is available in both 32-bit and 64-bit versions.
After you download and install the update, you can enable or disable data co-location using DPM Management Shell.

Enabling Data Co-Location on DPM 2007

  1. Open DPM Management Shell.

  2. Set -OptimizeTapeUsage to True using the Set-DPMGlobalProperty cmdlet.
    Set-DPMGlobalProperty -DPMServerName <name of DPM server> -OptimizeTapeUsage $True

After data co-location has been enabled, DPM will check for the following conditions before allocating a tape:

  • The expiry date of the current dataset should fall in between the following dates:
    Upper bound: furthest expiry date among all the datasets on the tape - (furthest expiry date among all the datasets on the tape - current date) * ExpiryToleranceRange
    Lower Bound: furthest expiry date among all the datasets on the tape + (furthest expiry date among all the datasets on the tape - current date) * ExpiryToleranceRange.

  • Current time should be less than first backup time of the dataset on the media + TapeWritePeriodRatio * RetentionRangeOfFirstDataset.

A dataset will be co-located only if both the above conditions are true.

Term Description

TapeWritePeriodRatio

Indicates the number of days for which data can be written on to a tape as a fraction between 0 and 1. The default value is 0.15.

ExpiryToleranceRange

Indicates the time window within which the expiry date of the dataset to be written to the tape must fall. It is expressed as a percentage. The default value is 17 percent.
This is a DWORD type registry value located under HKLM\Software\Microsoft\Microsoft Data Protection Manager\1.0\Colocation. DPM does not create this key automatically. You must manually create this key if you want to set the ExpiryToleranceRange.

Note

When tape colocation is enabled, a tape on to which offsite backup is written will not be shown as Offsite Ready unless one of the following conditions are met:

  • The tape is full.

  • One of the datasets has expired.

  • Write-period ratio has been crossed. (By default, this is first backup time + 15 per cent of retention range.)

Disabling Data Co-Location on DPM 2007

  1. Open DPM Management Shell.

  2. Set -OptimizeTapeUsage to False using the Set-DPMGlobalProperty cmdlet.
    Set-DPMGlobalProperty -DPMServername <name of DPM server> -OptimizeTapeUsage $False

Restrictions

The following restrictions apply to using data co-location in DPM:

  • You cannot apply co-location selectively. If enabled, it applies to all protection groups.

  • Only protection groups with the same retention period can be co-located on the same tape.

  • Encrypted and non-encrypted datasets cannot be co-located on the same tape.

  • Datasets from different vaults cannot be co-located on the same tape.

  • Protection groups configured for “Full and Incremental” cannot be co-located with those configured for “Full Backup Only”.