Why don't the data sources actually colocate? RRS feed

  • Question

  • I am creating a protection group of around 40+ SQL Server databases.
    I do this via powershell script
    		$pg = New-ProtectionGroup -dpmServerName $dpmServerName "$pgName Database PG"
    		$mpg = Get-ModifiableProtectionGroup $pg
    		foreach($t in $dataSourceList) {
    			Add-ChildDataSource -ProtectionGroup $mpg -ChildDataSource $t
    			Set-PolicyObjective -ColocateDataSources $true -ProtectionGroup $mpg
    			$diskAlloc = Get-DatasourceDiskAllocation -DataSource $t
    			Set-DatasourceDiskAllocation -DataSource $t -ProtectionGroup $mpg

    the details of the protection group are shown below
    And this is how my NT disk volumes look

    I have never ever understood this behavior... If I am saying that "ColocateDatasources" then why so many volumes? What is the meaning of Colocation of Datasources!!

    MSDNStudent Knows not much!

    Wednesday, October 5, 2011 10:52 AM


  • Thank you for the update.

    The reason for having that many volumes is because by default DPM allocates 10 GB for replica and a maximum of 30 SQL databases can be used in that replica.

    If couple SQL DBs fill out that 10 GB replica, then a new 10 GB replica will be created to accommodate the remaining SQL DBs and so forth.

    You can change the default behavior by editing the following registry key on your DPM Server:

    HKLM\Software\Microsoft\Microsoft Data Protection Manager\Collocation\sql

    CollocatedReplicaSize - Replica Size in Bytes, Default = 10737418240 (decimal)

    DSCollocationFactor - Amount DBs in a single replica, Default = 30 (decimal)

    Hope this helps.


    Thanks, Wilson Souza - MSFT This posting is provided "AS IS" with no warranties, and confers no rights
    Tuesday, October 11, 2011 7:46 AM

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