Hi Nishan, If your vm is deployed in an isolated network all the traffic goes via VR. So please check the rate limiting on the VR. You may have to increase the rate limit value to get more BW.
Thanks, Sanjeev -----Original Message----- From: Nishan Sanjeewa Gunasekara [mailto:nishan.sanje...@gmail.com] Sent: Wednesday, March 05, 2014 10:02 AM To: users Subject: Disk IO on Cloudstack VMs 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