Dear Richard!
Unfortunately, to use Xen with "tap:aio" to mount disk image, requirement
with GlusterFS is use --disable-direct-io-mode, because otherwise Xen
return an error on device.
Worst aspect with use disable direct io mode are that read and write
forgiveness a 50% of performance.
(max write in new file 101Mb/s and in rewrite 67,8Mb/s)
It's a very disaster, although connection from servers are gived by
Infiniband (10x)
I does not have idea if is possible, in a future, solve this aspect
(must mount with disable direct io mode to use
with Xen) but, for me, at this moment GlusterFS are a very very good
filesystem, but is not an optimal
choice to use for Xen storage.
Enrico
Have you tried with io-threads on the server side?
Avati
2009/2/21 Richard Williams <richard@xxxxxxxxxxxxx>:
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
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