Re: [Iscsitarget-devel] Best settings for VMware Cluster

[Ross W. <rsw...@gm...>]

On Apr 19, 2009, at 10:28 PM, Ryan Whelan <rcw...@gm...> wrote:

> I've seen the topic of using IET for vmware clusters numerous times
> over the last couple years- has there been a consensus on what is the
> best setup/config for concurrent access for ESX machines to shared
> LUNs?
>
> If its a matter of RTFM, I'll accept on list lashings

No, there is no consensus on which is best, but there are lots of  
opinions.

Fiber, iSCSI or NFS?

For me I started with iSCSI for all VMware storage, then I switched to  
NFS for the OS disks using iSCSI within the guests themselves for  
application data.

The idea was to leverage the thin provisioning of NFS to reduce waste  
on OS images, which has worked well, saved 50% of high cost RAID10  
storage. NFS also allows better multi-threaded IO operation so with a  
high number of VMs you can scale the storage to handle the IOPS where  
as with iSCSI the single disk queue on the ESX initiator often becomes  
a bottleneck, but NFS caps max sustained throughput in the 30-40MB/s  
range, where with iSCSI I can get 115MB/s max sustained, so for those  
applications that require high performance storage I bring iSCSI into  
the VM.

Works well so far.

-Ross