[Users] Extremely poor disk access speeds in Windows guest

[Steve Dainard]

I've reconfigured my setup (good succes below, but need clarity on gluster
option):

Two nodes total, both running virt and glusterfs storage (2 node replica,
quorum).

I've created an NFS storage domain, pointed at the first nodes IP address.
I've launched a 2008 R2 SP1 install with a virtio-scsi disk, and the SCSI
pass-through driver on the same node as the NFS domain is pointing at.

Windows guest install has been running for roughly 1.5 hours, still
"Expanding Windows files (55%) ..."

top is showing:
  PID USER      PR  NI  VIRT  RES  SHR S %CPU %MEM    TIME+  COMMAND

 3609 root      20   0 1380m  33m 2604 S 35.4  0.1 231:39.75 glusterfsd

21444 qemu      20   0 6362m 4.1g 6592 S 10.3  8.7  10:11.53 qemu-kvm


This is a 2 socket, 6 core xeon machine with 48GB of RAM, and 6x 7200rpm
enterprise sata disks in RAID5 so I don't think we're hitting hardware
limitations.

dd on xfs (no gluster)

time dd if=/dev/zero of=test bs=1M count=2048
2048+0 records in
2048+0 records out
2147483648 bytes (2.1 GB) copied, 4.15787 s, 516 MB/s

real 0m4.351s
user 0m0.000s
sys 0m1.661s


time dd if=/dev/zero of=test bs=1k count=2000000
2000000+0 records in
2000000+0 records out
2048000000 bytes (2.0 GB) copied, 4.06949 s, 503 MB/s

real 0m4.260s
user 0m0.176s
sys 0m3.991s


I've enabled nfs.trusted-sync (
http://gluster.org/community/documentation/index.php/Gluster_3.2:_Setting_Volume_Options#nfs.trusted-sync
) on the gluster volume, and the speed difference is immeasurable . Can
anyone explain what this option does, and what the risks are with a 2 node
gluster replica volume with quorum enabled?

Thanks,
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.ovirt.org/pipermail/users/attachments/20140131/e0552b87/attachment-0001.html>