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Re: Solution Needed for Snapshot Dilemma


Solution Needed for Snapshot Dilemma

We have 3 HP P4300G2 Nodes in one cluster that is running SAN/iQ 9.5 in our primary location and we have another P4300G2 unit in our DR location.


We also have 3 HP DL380 G7 servers running ESXi 4.1 U2 in our main location and 1 HP DL380 G7 for DR.


All of our VM's in the main location are split amongst 3 datastore volumes which are on the SAN and they are connected via the ESXi software iSCSI initiator.


Our Exchange and SQL log & DB volumes are connected via the MS iSCSI initiator from the guest OS.


The goal is to be able to use Remote Copy of Application Managed Snapshots of both the datastore and Exchange/SQL volumes so that we can have copies of those volumes in our DR location and that we can turn up whichever VM's are the most critical on our 1 HP DL380 G7 in case of a disaster.


The dilemma is that we are able to get application managed snapshots of the Exchange/SQL DB/Log volumes to work properly with the Lefthand VSS provider installed on our Exchange/SQL guests.


But we are not able to get the application managed snapshots of our datastore volumes which is one of the new features of SAN/iQ 9.5 to work properly. When we attempt a application managed snapshot, the VM's that have iSCSI initiator configured to data volumes don't complete their ESXi snapshots properly. They get stuck at 95% and the VM's become inaccessible via the network.


My research has indicated that this may be due to the fact that ESXi snapshots are not supported when using the iSCSI initiator in the guests. See the following ESXi KB



But if I switch my connections to the Exchange/SQL volumes from the guests to use RDM instead of iSCSI inside the guest, then I won't be able to properly take a Lefthand application managed snapshot of those Exchange/SQL data volumes since the communication to the VSS provider needs to happen with the iSCSI initiator directly through the guest (or so I am told.....Someone correct me if I am wrong)


As such...I can't seem to be able to get application managed snapshots of everything (vmdk volumes & Exchange/DB data volumes) to remote copy to our DR node.


Does anyone have any ideas on how to make this work or am I stuck with just plain snapshots of datastore volumes and therefore I have to pray that they can boot up when a disaster strikes.


Thanks in advance






Re: Solution Needed for Snapshot Dilemma

Why not migrate away from in-guest iSCSI initiators and also away from RDM, and start using plan old VMFS datastore hosted vmdk's for the Exchange and SQL data?

This way you have a simplified DR plan and the application managed snapshots should work fine.

If my post was useful, clik on my KUDOS! "White Star"

Re: Solution Needed for Snapshot Dilemma

From what I was told from Lefthand support, application managed snapshots for Exchange & SQL data/log volumes will not work if those volumes are stored in VMDK volumes as the SAN won't be able to access the data unless it can see it through the iSCSI initiator.


Are you saying this may not be true?


Are things different with SAN/iQ 9.5 where if you have the Exchange & SQL data/log volumes as VMDK volumes, then when you take an application managed snapshot of the OS drive using vCenter, then it will also create a snapshot of the Exchange & SQL data volumes?


Re: Solution Needed for Snapshot Dilemma

Anybody else have anything to comment about my situation?


Do I have my facts wrong?