none
Disk Co-location question

    Question

  • Hello

    We have DPM 2012 SP1 protecting a few non clustered Hyper-V hosts and one is being decomissioned.

    I have been progressively moving VM's across these hosts and manually editing the Protection Groups within DPM, removing the VM source from the old host/PG to the new host/PG.

    Disk Co-location is enabled on both PGs and what I have ended up with is several Co-Located volumes under the new host/PG with the protected VMs spread across.

    - ideally, shouldn't only one co-located storage volume be used for the VMs?
    - can VMs backed up by Saved State and Child Partition Snapshots be co-located?
    - how can I correct this? Can I do it without re-creating the protection group and loosing the replicas and recovery points?

    Thanks

    Monday, August 05, 2013 2:01 AM

Answers

All replies

  • Hi,

    Ideally you want to use DPM 2012 Sp1 feature that allows DPM to follow the Virtual machine using Live migration, that way DPM will maintain protection in a hands off way.

    Protecting virtual machines during live migration
    http://technet.microsoft.com/en-us/library/jj656643.aspx

    http://blogs.technet.com/b/dpm/archive/2013/04/24/sc-2012-sp1-dpm-windows-2012-vm-mobility-uninterrupted-data-protection.aspx

    This requires Windows 2012 Hyper-V servers, but well worth the upgrade if you are not already on Server 2012. 

    The state that the VM can be protected (backup using saved state or child partition) has no effect on co-location.


    Please remember to click “Mark as Answer” on the post that helps you, and to click “Unmark as Answer” if a marked post does not actually answer your question. This can be beneficial to other community members reading the thread. Regards, Mike J. [MSFT] This posting is provided "AS IS" with no warranties, and confers no rights.

    Monday, August 05, 2013 6:17 PM
    Moderator
  • Thank you Mike, although I have been moving these VM's to decomission the old host only. Under normal circumstances these VM's won't be moving between hosts.

    Are you able to explain if having multiple co-located volumes with the VM's spread across is the norm? shouldn't they all be co-located under the one volume? and if so how can i correct this or will it correct itself once the data retention rates expire?

    Tuesday, August 06, 2013 12:27 AM
  • Hi,

    The default Hyper-V Co-located replica volume that DPM creates by default is 250GB meaning we will co-locate as many Hyper-V  guests that fit on that 250GB volume up to 8 before we create another 250GB volume.

    Depending on your average Hyper-V guest, you can modify that registry key so you can take better advantage of the co-location feature.

    Key name: HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Microsoft Data Protection Manager\Collocation\HyperV
      Valuename= CollocatedReplicaSize and should be a multiple of 1GB  (1073741824 bytes)

    Now, for you to do this, you would need to perform the following steps.

    1)  Calculate the average size HyperV  guest under protection, and plan for some growth over time.
    2) Multiply the (average size + growth) * 8  – this will be the new collocatedreplicaSize – make sure it’s a multiple of 1GB  (1073741824 bytes)
    3) Modify the registry key to make it that new value.
    4) DPM will make new larger replica volumes and co-locate up to 8 Guests per replica.

    Enabling Data Co-Location

    http://technet.microsoft.com/en-us/library/jj628042.aspx


    Please remember to click “Mark as Answer” on the post that helps you, and to click “Unmark as Answer” if a marked post does not actually answer your question. This can be beneficial to other community members reading the thread. Regards, Mike J. [MSFT] This posting is provided "AS IS" with no warranties, and confers no rights.

    Tuesday, August 06, 2013 12:53 AM
    Moderator
  • Thanks once again Mike and sorry I did not find that info on my own accord.

    One last question on this topic, once the registry change has been made do I need to do anything or just be patient and let DPM sort itself out over the retention period?

    I'm hoping I do not need to re-create the protection groups, but please let me know.

    Tuesday, August 06, 2013 2:02 AM
  • Hi,

    Only new replicas created and new protected guests will adhere to the new settings. You can use this DPM powershell script to see what guests are located on what replica.

    cls
    $color = 'white' 
    $pg = Get-ProtectionGroup (&hostname) 
    foreach ($pg1 in $pg)
    {
    	write-host "Protection Group " $pg1.friendlyname -f yellow
    	$ds = @(Get-Datasource $pg1 | sort-object -Property replicapath)
    	$count = 0
    	write-host
    	write-host  "   Colocated Replica Size        Used Datasource Name"
    	write-host  "   --------- ------------ ----------- --------------------------"
    	while ($count -lt $ds.count)
    	{
    		$dscolocation = @($ds | ? { $_.replicapath -eq $ds[$count].replicapath })
    		if ($dscolocation.count -gt 1)
    		{
    			foreach ($dc in $dscolocation)
    			{
    				$split = $dscolocation[0].diskallocation -split ' '
    				$rs = $split[3] + " " + $split[4] # replica size
    				$size = (Get-ChildItem $dc.ProtectableObjectLoadPath.values -recurse | Measure-Object -property length -sum).sum /1024/1024/1024
    				write-host ("   Yes  {0,17} {1,8:N2} GB {2,-50}" -f $rs, $size, $dc.DisplayPath) -f $color
    				$count++
    			}
    		}
    		else
    		{
    			$split = $dscolocation[0].diskallocation -split ' '
    			$rs = $split[2] + " " + $split[3] # replica size
    			$ru = $split[5] + " " + $split[6] # replica used by the datasource
    			write-host  ("   No   {0,17} {1,11} {2,-50}" -f $rs, $ru, $dscolocation[0].DisplayPath) -f $color
    			$count++
    		}
    		if ($color -eq 'white') { $color = 'cyan'} else { $color = 'white'}
    	}
    	write-host


    Please remember to click “Mark as Answer” on the post that helps you, and to click “Unmark as Answer” if a marked post does not actually answer your question. This can be beneficial to other community members reading the thread. Regards, Mike J. [MSFT] This posting is provided "AS IS" with no warranties, and confers no rights.


    Tuesday, August 06, 2013 3:35 AM
    Moderator