In a recent conversation with Eddie Tang and Anagha from engineering - I have learned a crucial piece of information on VSS + RDM in VMware environment (this will go into the next revision of VMW BPG for sure) - in the meantime, be sure to keep the following 'gotcha' in mind!
When RDM is used, VMware ESX would NOT take a snapshot of the RDM, so one would need to install NPM/NWT to leverage the nimble VSS requestor & provider
1)NWT(nimble windows toolkit) VSS requester will connect to the snapshot of those volumes on the array for verification. This is the iSCSI connection to the snapshot target on the array. So, you need to have iSCSI initiator service started in the guest and the discovery IP of the array should be added
2)because snapshot will be connected from the guest OS, the initiator group ACLs must be set up correctly to allow the iSCSI initiator in the guest OS access to the snapshots of the RDM volume
I'll update my blog with a new mini post to include this information.
Wen -- our recent survey of ~500 IT professionals found that more than half of the deployments are using VMDKs for their application data and ~50% of the deployments were taking VM consistent backups. Looks like VSS integration in the VMware environment is a key part of their data protection strategy.
This is a great write-up Wen. From our perspective, we think it's very important for customers with large SQL database servers (i.e. Data Warehouse servers with multiple TBs of mdf files), to take the iSCSI Initiator/VSS path, seriously.
We tried running 4 TBs split amongst 4 VMDK files. However, once the snapshot count started getting up there, VMware started firing off latency errors.
I'm definitely a fan of iSCSI Initiators on SQL DB servers now.
The Troubleshooting section will be much appreciated.