VMware Disastery Recovery & frozen I/O in MSSQL

[chase1124]

Hi Guys,

I notice that when the backup job starts for the Disaster Recovery VM, I get the following messages in my windows server event logs.

I/O is frozen on database model. No user action is required. However, if I/O is not resumed promptly, you could cancel the backup.

I/O was resumed on database model. No user action is required.

Database backed up. Database: model, creation date(time): 2003/04/08(09:13:36), pages dumped: 1, first LSN: 250:160:34, last LSN: 250:184:1, number of dump devices: 1, device information: (FILE=1, TYPE=VIRTUAL_DEVICE: {'{670DA95B-90F0-4717-8AAD-1226E8753BAA}1'}). This is an informational message only. No user action is required.

Where this message is repeated for each database on the sql server and not just the 'model' database.

Is this normal? Why is this happening? I thought Disaster Recovery just backed up the vmdk file by creating a snapshot. Should I worry that I/O is being temporarily frozen on all my databases (and thus could become stuck in this frozen state at some point)? And does this imply that I should be able to individually recover each database via VMware Disaster Recovery independently of the full virtual machine restore?

[DSTAVERT]

As part of the quiescing operation all writes are suspended in order to get a consistent snapshot.

[chase1124]

So, VDR requires the quiesced snapshot and tells VMWare tools to send some command to VSS and that is what generates this output from SQL Server? It certainly seems like there is some backup operation happening on each of the databases and not just a system-wide suspension of writes, but should I just ignore this as misleading output due to the quiescing?