[Gluster-users] Performance issues on GlusterFS with KVM/qcow2

Tobias Andersson tobias at tobiasa.se
Wed Jan 25 15:54:43 UTC 2012

On 01/25/2012 02:24 PM, Giovanni Toraldo wrote:
> Hi Tobias,
> 2012/1/25 Tobias Andersson<tobias at tobiasa.se>:
>> Write test 2, VM (Debian 6, VirtIO, stored as qcow2 on /vm_storage):
> qcow2 performances are strictly depending on qcow2 preallocation
> feature. You may also want to test with a RAW image type and report
> back.

Hi there,

Thank you for your answer.

I just tested the same procedure with a new Debian 6 guest on a RAW 
image and got the same results there.

628+0 records in
4628+0 records out
4852809728 bytes (4.9 GB) copied, 709.649 s, 6.8 MB/s

real    11m50.169s
user    0m0.000s
sys     0m5.756s

So it seems it's not related to qcow2 then. Can it be VirtIO drivers 
that are not performing well with GlusterFS?

My current setup allows me to do writes in over 60-70 MB/s to a GFS2 
filesystem on a central SAN so I don't see why GlusterFS should perform 
this bad with the same underlaying virtualization setup. Any clue?

Best regards,

Tobias Andersson
Please avoid sending me Word, Excel or PowerPoint attachments.
See http://www.gnu.org/philosophy/no-word-attachments.html

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