[Rdo-list] cinder speed (slow nova?)

[Kaul, Yaniv]

> -----Original Message-----
> From: rdo-list-bounces at redhat.com [mailto:rdo-list-bounces at redhat.com] On
> Behalf Of Dmitry Makovey
> Sent: Tuesday, December 23, 2014 1:10 AM
> To: rdo-list at redhat.com
> Subject: [Rdo-list] cinder speed (slow nova?)
> 
> Hi everybody,
> 
> using RDO IceHouse packages I've set up an infrastructure atop of
> RHEL6.6 and am seeing a very unpleasant performance for the storage.
> 
> I've done some testing and here's what I get from the same storage: but
> different access points:
> 
> cinder-volume # dd if=/dev/zero of=baloon bs=1048576 count=200
> 200+0 records in
> 200+0 records out
> 209715200 bytes (210 MB) copied, 0.162997 s, 1.3 GB/s

You are testing the performance with the cache. Use direct IO, to bypass it.
Y.

> 
> nova-compute # dd if=/dev/zero of=baloon bs=1048576 count=200
> 200+0 records in
> 200+0 records out
> 209715200 bytes (210 MB) copied, 0.167905 s, 1.2 GB/s
> 
> instance # dd if=/dev/zero of=baloon bs=1048576 count=200
> 200+0 records in
> 200+0 records out
> 209715200 bytes (210 MB) copied, 10.064 s, 20.8 MB/s
> 
> A bit of explanation: in above scenario I have created LV on cinder-node, then
> mounted it locally and ran command for "cinder-volume". Created an iSCSI
> target, mounted it on nova-compute, and ran command there. Then, via cinder
> created storage volume, booted the OS off it, and ran test from within it...
> Results are just miserable. going from 1.2G/s down to 20M/s seems to be a big
> degradation. What should I look for? I have also tried running the same
> command within our RHEL KVM instance and got great performance.
> 
> I have checked under /var/lib/nova/instances/* and libvirt.xml seems to
> indicate that virtio is being employed:
> 
>     <disk type="block" device="disk">
>       <driver name="qemu" type="raw" cache="none"/>
>       <source
> dev="/dev/disk/by-path/ip-192.168.46.18:3260-iscsi-iqn.2010-
> 10.org.openstack:volume-955b25eb-bb48-43c3-a14d-222c9e8c7019-lun-1"/>
>       <target bus="virtio" dev="vda"/>
>       <serial>955b25eb-bb48-43c3-a14d-222c9e8c7019</serial>
>     </disk>
> 
> guest used - is rhel-guest-image-6.6-20140926.0.x86_64.qcow2 downloaded off
> RH site.
> 
> --
> Dmitry Makovey
> Web Systems Administrator
> Athabasca University
> (780) 675-6245
> ---
> Confidence is what you have before you understand the problem
>     Woody Allen
> 
> When in trouble when in doubt run in circles scream and shout
>      http://www.wordwizard.com/phpbb3/viewtopic.php?f=16&t=19330