From: Kevin Thorpe
Date: Friday, June 21, 2013 8:14 AM
Subject: [HPDD-discuss] Wondering about running OSTs on my cloud platform.
Hi, we've been looking at private (and maybe hybrid) cloud provisioning. We've
an architecture for the traditional SAN + hosts model but we're interested in the
SANless SAN devices that Nutanix offer. We realise that a hardware SAN device
is more likely to deliver performance but we think we could get away with using
distributed local storage on the VM host servers.
Do you think that running an OST VM on each of our VM hosts utilising local disks
would be a sensible thing to do? I realise this would eat into RAM and processor
on each host, but new hosts would be far cheaper than a SAN device. I'm particularly
interested in the ZFS option so se get SSD cache on each node. The only thing
that I can see that Nutanix do that Lustre can't is migrate data to the nodes using
that data, or am I wrong on that?
Chief Technical Officer
Sorry, bad mail options, resending with proper format
Running an OST on a VM, critical item is how much the VM throttles IO/network bandwidth.
Lustre itself is happy on VM but getting real-iron IO bandwidth can be an issue.
From my limited understanding it depends a lot on how well your
particular hardware lines up with support in the VM.
You should be able to test that
without Lustre, or with a fairly simple Lustre setup. You could compare sgpdd-survey
results with/without the VM.
Second question is what is the delta between 'local disk' and the storage
That's totally dependent on the iron you have, and what you consider to be an
acceptable cost/performance trade.
Again, you can benchmark the local disk without Lustre and have a fairly good estimate.
Lustre does not migrate data, you are correct in that.