On Wed, 27 Jun 2012, Brian Candler wrote:
I've made a test setup like this, but unfortunately I haven't yet been able
to get half-decent performance out of glusterfs 3.3 as a KVM backend. It
may work better if you use local disk for the VM images, and within the VM
mount the glusterfs volume for application data.
What is considered half-decent? I have a 8 cluster distribute+replicate
setup and I am getting about 65MB/s and about 1.5K IOPS. Considering that
I am only using a single two disk SAS strip in each host I think that is
not bad.
Alternatively, look at something like ganeti (which by default runs on top
of drbd+LVM, although you can also use it to manage a cluster which uses a
shared file store backend like gluster)
Maybe 3.3.1 will be better. But today, your investment in SSDs is quite
likely to be wasted :-(
The idea is to have HA if either one KVM hypervisor or one Glusterfs
server stop working (failure, maintenance, etc).
You'd also need some mechanism for starting each VM on node B if node A
fails. You can probably script that, although there are lots of hazards for
the unwary. Maybe better to have the failover done manually.
Also check out oVirt, it integrates with Gluster and provides HA.
2. We still didn't decide what physical network to choose between FC, FCoE
and Infiniband.
Have you ruled out 10G ethernet? If so, why?
I agree, we went all 10GBase-T.
(note: using SFP+ ports, either with fibre SFP+s or SFP+ coax cables, gives
much better latency that 10G over RJ45/CAT6)
Actually with the new switches like Arista this is less of an issue.
3. Would it be better to split the Glusterfs namespace into two gluster
volumes (one for each hypervisor), each running on a Glusterfs server
(for the normal case where all servers are running)?
I don't see how that would help - I expect you would mount both volumes on
both KVM nodes anyway, to allow you to do live migration.
Yep
<>
Nathan Stratton
nathan at robotics.net
http://www.robotics.net
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