VM Access to SAN

[ronald_higgins]

Greetings,

I'm sure some of you will know the answer quick sticks from the top of your head.

I'm none too strong on the matter.

Can VM's have access to SAN storage? My initial thoughts is no, as you would need a virtual hba adaptor to attach to the VM, which there isnt.

Basically the scenario is this. There is a physical host that is attached to a LUN. The idea was floated to have a VM run an a warm standby and should the need arise, switch over to

the VM which will have access to the LUN.

So, as far as I know, this isnt possible but i'm sure some have you have had this scenario before.

[ronald_higgins]

Edit. Too provide clarity as there is a sorta similar thread further below.

Physical host is a mailserver, and the mail is stored on the LUN.

So the scenario is too switch over to the VM and have the VM access the LUN much like the physical did.

[weinstein5]

What you are referring to is an RDM - Raw Device Mapping - this allows a VM to write directly to a LUN on the SAN - check out for steps on how to create an RDM. what you are looking at accomplishing is to set up a physical to virtual cluster - check out this for some guidance to do it with MS Clustering Services -

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[JaySMX]

Yes, it is possible to give a VM direct access to a LUN using a DRM. If sounds like you are trying to configure a high-availability cluster between a physical server and a VM, is that right? If so, check out this link (assuming you are using Windows):

[ronald_higgins]

Fortunately no ... is a Redhat ES Server :smileygrin:

But thanks for the links, i'll take a squiz and see if it still applies.

[Texiwill]

Hello,

THe MSCS document provided is the proper one for any form of shared disk cluster whether using Windows or Linux. As for using a LUN as part of your RedHat ES system, that is possible using either an official RDM (for remote storage) or a Raw SCSI Device (for local storage). I do this with no issues.

Best regards,

Edward L. Haletky

VMware Communities User Moderator

====

Author of the book 'VMWare ESX Server in the Enterprise: Planning and Securing Virtualization Servers', Copyright 2008 Pearson Education.

CIO Virtualization Blog: http://www.cio.com/blog/index/topic/168354

As well as the Virtualization Wiki at http://www.astroarch.com/wiki/index.php/Virtualization

[ahrqnag]

What about when using a backup application like Veeam in a VM-how do you give this VM access to all of the files in the datastore to allow for backups? I have added an RDM but this is serving only as the destination for the backup images. Typically, I use physical servers that are SAN-connected and add the LUNs from our VM storage groups into this storage group (running diskpart automount disable of course to avoid corruption) and this works flawlessly and fast. I don't see a way to do get the same direct SAN access as a physical machine can get....MSCS and other app-specific configs aside. This is what I get when I try to back up other VMs using Veeam in SAN-ONLY modeyou would typically see this on a physical server as well IF you did not add the Datastore LUNs into its storage group on the SAN....it needs read-only access to all of the LUNs used by the ESX hosts. For MSCS, RDMs work fine BUT we just set up a cluster using shared virtual disks which is better...no need for RDMs but this is with vSphere 4...not 3.5

Unable to establish direct connection to the shared storage (SAN).

Please ensure that:

- HBA is properly installed in the Veeam Backup server computer, or software iSCSI initiator is configured correctly.

- SAN volume can be seen by operating system in the Windows Disk Management snap-in on the Veeam Backup server.

- Read access is allowed for the Veeam Backup server computer on the corresponding LUN (refer to your SAN documentation).

Hope this info helps,

Cheers