[ovirt-users] Best practice for iSCSI storage domains

[Christopher Cox]

On 12/07/2017 01:10 AM, Richard Chan wrote:
> What is the best practice for iSCSI storage domains:
> 
> Many small targets vs a few large targets?
> 
> Specific example: if you wanted a 8TB storage domain would you prepare a 
> single 8TB LUN or (for example) 8 x 1 TB LUNs.

There's no "best" answer for this.  However, if you know you're going to 
be doing a ton of VMs (storage), then less is best.  The problem with 
"less" is that you might end up wasting more space for longer periods of 
time.  Not necessarily an issue for subsystems with thin provisioning, 
but just something to be aware of.

The number of virtual disks can get extreme.  And while that's not 
really related to the iSCSI, just getting all those virtual disks online 
(for example, after node maintenance) can get time consuming.

Took me over 30 minutes the other day.

Obviously that tends to get worse as the number of virtual disks increases.

So, there is something to be said about trying to reduce the number of 
virtual disks.

Our standard for new storage domains is 6TB.