On 2013-07-10T08:31:17, Ulrich Windl <ulrich.wi...@rz.uni-regensburg.de> wrote:
> I had reported about terrible performance of cLVM (maybe related to using
> OCFS also) when uses in SLES11 SP2. I guesses cLVM (or OCFS2) is
> "communicating to death" on activity. Now I have some interesing news:
No, the performance issue with cLVM2 mirroring is not at all related to
OCFS2; that's just cLVM2's algorithm being, well, suboptimal.
> on top of cLVM/OCFS I have image files for Xen VMs. I set up an OpenLDAP
> server in one of the VMs. Now about everytime the LDAP server gets an update
> (meaning id does some flushed disk writes), corosync reports a faulty ring.
> It's like:
That, though, clearly shouldn't happen. And I've never seen this,
despite hosting a "few" VMs on my OCFS2 cluster (even with cLVM2
mirroring).
Network problems in hypervisors though also have a tendency to be, well,
due to the hypervisor, or some network cards (broadcom?).
> # grep FAULTY /var/log/messages |wc -l
> 1546
>
> However the "FAULT" never lasts longer than one second.
That's weird. Multicast or unicast?
> OTOH our network guy says it's impossible to use the full network
> bandwidth. This makes me wonder: Is there a protocol implementation
> bug in TOTEM that is triggered when lots of packets arrive or when
> packets are delayed slightly, or is there a kernel bug that looses
> packets?
My guess would be the latter here.
Can this be reproduced with another high network load pattern? Packet
loss etc?
> Is there any perspective to see the light at the end of the tunnel? The
> problems should be easily reproducable.
Bugs that get reported have a chance of being fixed ;-)
Regards,
Lars
--
Architect Storage/HA
SUSE LINUX Products GmbH, GF: Jeff Hawn, Jennifer Guild, Felix Imendörffer, HRB
21284 (AG Nürnberg)
"Experience is the name everyone gives to their mistakes." -- Oscar Wilde
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