Hi Vaughn,
For small environments on a budget where the cost of additional licenses is an issue, you can use RDM's over iSCSI or FCP for both data LUN's _and_ the VM OS images. You still need VMDK pointer files to enable vmotion.
By using RDM's for the VM images you can use lun cloning for R/W snapshots within the same FlexVol, without paying for a FlexClone license and achieve a reasonable level of deduplication without paying for an A-SIS licence. i.e. create "golden images" as source LUNs then use lun clones for the prod, dev, test and backup images of the VM's.
However, for larger environments using vmdk's on NAS from NFS exports or CIFS shares for the VM images is a far more scalable and manageable solution as long as you're happy to pay for A-SIS to manage deduplication. I still wouldn't be putting data volumes inside the vmdk's though.
(Yes, you can use CIFS for vmdk's in ESX. Not as ideal as NFS for a whole bunch of reasons, but it works via the VMWare ESX CIFS driver and useful if you have to have CIFS for file server consolidation and don't want to pay for NFS licencing as well).
Either way, storing your application data in either RDM LUN's or as direct NAS shares makes managing snapshots for dev/test copies and online backups of the production data much simpler to manage. Putting data inside vmdk's limits your functionality particularly for backups.
MSCS requires an RDM for the quorum disk, but you can still use a NAS share for the data if your data profile and application characteristics indicate that it makes more sense to do that than use an RDM for the data.
regards,
Alan McLachlan.
-----Original Message----- From: owner-toasters@mathworks.com on behalf of M. Vaughn Stewart Sent: Sun 10/28/2007 8:07 AM To: Jack Lyons Cc: Page, Jeremy; toasters@mathworks.com Subject: Re: A-SIS questions
FlexClone will clone a datastore, for VM level cloning granularity you gonna have to wait I think something is just around the corner.
As for MSCS you need RDMs as VMDKs are not supported with MSCS
RDMs can be either FCP or iSCSI VMDKs can be on NFS or VMFS (which is over FCP or iSCSI)