Enabling Data Co-Location

Applies To: System Center Data Protection Manager 2010

Enabling Data Co-Location on DPM

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:

1. 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.

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

A dataset will be collocated 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 co-location 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.)