[Gluster-devel] Performance in Xen HVM using loop/img based disk file

[Richard Williams]

Right now I'm testing things out, trying to get Xen going using gluster as the storage back end.
I have a pretty simple setup at the moment.

1 server running Xen 3.3.1/Debian Etch(gluster client)
1 server running openfiler 2.3 (gluster server)

Networking on gluster client:
2 gigabit nics in bond0 (mode4)
bond0 is bridged with xenbr0
Xen adds virtual interfaces to the xenbr0 bridge for the virtual machines..
Basically all externally bound traffic goes through xenbr0, then bond0 which is then balanced over eth0 and eth1

Networking on gluster server:
2 gigabit nics in bond0 (mode4)
All external traffic goes through bond0

Gluster version on server and client:
# glusterfs --version
glusterfs 2.0.0rc1 built on Feb 17 2009 10:28:23
Repository revision: glusterfs--mainline--3.0--patch-844

Fuse on gluster client:
I believe I'm using the Gluster patched fuse, but I'm not sure.
When I tried to compile fuse, it said that the module was in the kernel.
So I tried to compile gluster, and it didn't see fuse.
So I tried to modprobe fuse but it wasn't there.
Then compiled fuse using  the -enable-kernel-module option to force fuse to compile.
Then I compiled gluster.

Fuse on gluster server:
I think I'm using the fuse that came with Openfiler 2.3
(again, not sure how to check at this point)

Ok, so basically everything is generally working great as far as I can tell - no errors in logs, etc.
I'm running windows 2008 on Xen and all is functioning... except one thing.

Whenever I put a decent bit of Disk I/O on the virtual machine.. such as downloading a large file from the internet...
Then the virtual machine seems to hang 2-5 seconds, continues, then hangs, then continues, then hangs... as it's downloading the file.
The whole VM doesn't hang, however... any operation that does not require disk access will continue to run smoothly.

If I move the VM disk off of the gluster mount onto local storage, then everything runs fine.  Downloading a file runs quite smoothly then.

So I think it's gluster/fuse/networking related (maybe) but I don't know how to figure it out from here.
I've played with various performance translators and also disabling all performance translators.
All variations do not seem to have an impact on this issue at all.
I suspect it's something deeper or perhaps I'm just missing something with the performance translators...
Anyway, I will be willing to try any and all suggestions.
I would really love to have gluster working - it's the most innovative solution to storage that I've found for what I'd like to do.

Thanks!!

Richard Williams

My .vol files:

# file: /etc/glusterfs/glusterfs-client.vol
volume remote
  type protocol/client
  option transport-type tcp
  option remote-host 64.16.220.101  # can be IP or hostname
  option remote-subvolume tempvm-brick
end-volume

volume writebehind
  type performance/write-behind
  option block-size 128KB
  subvolumes remote
end-volume


# file: /usr/local/etc/glusterfs/glusterfs-server.vol
volume posix-tempvm-brick
 type storage/posix
 option directory /mnt/nasblock1vg/nasblock1ext3/tempvm-brick
end-volume

volume locks-tempvm-brick
 type features/locks
 subvolumes posix-tempvm-brick
end-volume

volume tempvm-brick
 type performance/io-threads
 option thread-count 8
 subvolumes locks-tempvm-brick
end-volume

volume server
 type protocol/server
 option transport-type tcp
option auth.addr.tempvm-brick.allow <masked ip addresses>
subvolumes tempvm-brick
end-volume

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://supercolony.gluster.org/pipermail/gluster-devel/attachments/20090220/dffa72d0/attachment-0003.html>