recommendations on disk/lun sizes

[wb2]

I'm looking for recommendations on the following:

Currently I have all my VMs scattered throughout all my luns which are 500GB each.  My VMs with large data disks use ms iscsi initiator to connect to the iscsi san directly.  Therefore these large volumes, some up to 2.5TB are not really in VMware at all.  I'm looking at changing that though.  We use Symantec Backup Exec 2010 VMware agent to backup the virtual machine files and the complexity of backing up the VM and then the iscsi volume seperately is kind of a pain.  I'm looking for recommendations on how others handle this.  Should I just create large VM disks?  Any issues with restoring if things go south?  Or anything else?

[MauroBonder]

I think that this article can be useful for you. http://www.yellow-bricks.com/2009/06/23/vmfslun-size/

[wb2]

Thanks.  I'll look that over.  How about performance.  should I keep my iscsi attached data drives the way they are with ms iscsi connections?  Or would I get better performance as vmware disks?

[MauroBonder]

i think that is better you use vmware disks, without ms iscsi, because with ms iscsi it´s same of overhead + overhead...this is bad. If you need access disk direct in Virtual Machine use Raw Device.

The best practices say: use dedicates network adapter to iscsi with mtu 9000.

see http://www.vmware.com/pdf/vsphere4/r41/vsp_41_iscsi_san_cfg.pdf

Please, don't forget the awarding points for "helpful" and/or "correct" answers.

Mauro Bonder - Moderator