[Linux-cluster] CLVM performance

Steven Whitehouse swhiteho at redhat.com
Thu Oct 25 12:21:22 UTC 2012


Hi,

On Wed, 2012-10-24 at 17:27 +0200, Andrew Holway wrote:
> On Oct 24, 2012, at 5:01 PM, Heiko Nardmann wrote:
> 
> > Am 24.10.2012 16:38, schrieb Andrew Holway:
> >> Hello,
> >> 
> >> Ive been doing some testing.
> >> I have an iSCSI device that I have set up with CLVM. 
> >> I have 4 physical hosts, all with top of the range xeons and 144GB ram. 
> >> I have 12 KVM machines per physical machine with a total of 48 VMs.
> >> Each KVM is mounted on a LV.
> >> The performance is not very good.
> >> I am not a fish.
> >> 
> >> Could CLVM be the bottleneck? Especially with so many LV's?
> >> I though I would ask before I set up 48 physical luns on the iSCSI device :)
> >> 
> >> Thanks,
> >> 
> >> Andrew
> >> 
> >> 
> >> 
> >> 
> > Looks like you should open a ticket with RedHat and give them/us some
> > more infos (including expected perf. vs. experienced perf., cluster
> > configuration) ...
> 
> That would be tricky! We don't have Redhat subscription!
> 
> In any case, Im just interested if it *could* be a problem. I will have to test this with no CLVM before I can open a ticket somewhere.
> 
> Ta,
> 
> Andrew
> 

What is it that is not working at the speed that you think it should?
Are you looking at disk throughput, or time taken to scan the LVs or
something else? Does the throughput improve if you use the iSCSI LUN
directly?

I think we'd need more information before this can be solved. Also I'd
suggest asking on the LVM list as there may be more people there who can
help.

Unless this is specifically about the cluster bit of CLVM (and the
cluster bit is only in use when configuration changes are made, or when
things are scanned at boot time) then that may be a better bet for
finding a solution,

Steve.






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