[Openstack] cinder slow (nova issues?)

Robert van Leeuwen Robert.vanLeeuwen at spilgames.com
Tue Dec 23 20:36:17 UTC 2014

> from above numbers it doesn't sound like storage node is the culprit -
> 50% drop happens on compute node going from baremetal to virtual. So I'm
> inclined to think it's a tuning of virtio (if that is even possible).

Some tuning tips for kvm: http://www.linux-kvm.org/page/Tuning_KVM

We saw a major improvement using RAW vs QCOW2 
(in theory this should be similar, however, when you need a high random IO throughput we did see major improvements in our setup with RAW)

On more thing to check is partition alignment. (not very likely for a recent OS)

Robert van Leeuwen

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