Expand SAN Storage Space Assigned to Mutiple ESX Servers

[phillipm]

Hi ! General SAN/VMWare Question!

We have a SAN VMFS that has now run out of diskspace and I am unsure what the consequences are if I were to expand the current VMFS assigned to the Various ESX Servers and Hosts...

So what are the things i need to watch out for if i wanted to expand the current storage space ..

[MR-T]

Just expanding the LUN on the SAN won't help you.

What you need to do is create another LUN and join this with the original by creating an extent.

Failing this, create a nice new large LUN and migrate the VM's into this.

[enDemand]

Another caveat would be your VMDK files that may be thin-provisioned. They cannot span extents, so if the original VMFS datastore is running out of room and your VMDK wants to grow, it cannot flow-over to the new LUN.

This is very rare, though, and only applies if you've used vmkfstools to thin-provision your virtual disks (most people don't).

[Texiwill · Accepted solution]

Hello,

The suggestion is to not use ESX extents except as a temporary measure. It is better to create a new LUN and move VMs to it to balance the load across multiple LUNs. You can reduce SCSI Reservation Conflicts and better balance your SAN load (depending if your SAN is active/active, active/passive, or you have more than one SAN) this way.

Best regards,

Edward

Message was edited by:

Texiwill