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From Nishan Sanjeewa Gunasekara <nishan.sanje...@gmail.com>
Subject Disk IO on Cloudstack VMs
Date Wed, 05 Mar 2014 04:31:41 GMT
Hi,

I'm running CS 4.2.1 on XenServer 6.2 hosts.

My primary storage is a ZFS file system provided via NFS.

When I do a dd test directly from one of the hosts on the NFS mount I get a
write speed of about 150MBps

 dd if=/dev/zero of=test.dmp bs=1M conv=fdatasync count=1000
1000+0 records in
1000+0 records out
1048576000 bytes (1.0 GB) copied, 6.99829 seconds, 150 MB/s

But when I do the same test on a Cloudstack VM running on the same host
(root disk on the same nfs mount ofcourse) I get a very low write speed.
20MBps.

 dd if=/dev/zero of=test.dmp bs=1M conv=fdatasync count=1000
1000+0 records in
1000+0 records out
1048576000 bytes (1.0 GB) copied, 44.6171 s, 23.5 MB/s

Any ideas how I can improve this ?

Regards,
Nishan

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