Data Backup and Recovery

LUNS or VDMKs in 4.1 VMWare


Sorry to sound like a newb but I am running VSphere 4.1 with 5 ESX node cluster. Up to this point when I create a new vm that requires multiple disks (SQL, Custom Apps, etc) I have done so by simply adding a disk through VSphere. The question is should I instead be installing Microsoft ISCSI initiator on the VM and creating LUNS for the addtional drives? Unfortunately I would have to make the connection to ISCSI over the same connections ESX uses to the NFS mount so I was not sure there would be any benefit since I can't separate the traffic. Thanks for any help.




I would say your vmdk approach was better.

If you directly map iSCSI LUN to VM, i.e. pass through LUN, its considered as RDM (neither VMware nor NetApp allows you to backup (protect) such disk).

If you are still keen on using iSCSI, you should map the LUN to ESX and then start creating vmdks out of it.



The approach we took was to present LUN's directly to the ESX hosts then add them to VM's as RDM's (Raw Device Mappings) within VSphere, you do however need to use a VMDK as a RDM placeholder if you want to v-motion etc. This is fully supported from NetApp and you can use this method with all Snap Manager products, SMSQL, SMSP, SMVI, SME etc.



I recommend looking at this doc for better understanding of key concepts:

"NetApp Storage Best Practices for VMware vSphere"

Kind regards,