[Gluster-users] Slow speed with Gluster Backed Xen DomU's

[Sheng yeo]

Hi Josy, 

Thanks for that :-). I'll give the new version a go. Out of curiosity
were you using this with Xen as a back end?

Thanks!


On Tue, 2010-07-20 at 06:54 +0200, it-news (Josef Lahmer) wrote:
> hi sheng,
> 
> i had heavy performace issues with 3.0.4.
> i recommend using glusterfs version 3.0.5. 
> 
> regards
> josy
> 
> > -----Ursprüngliche Nachricht-----
> > Von: gluster-users-bounces at gluster.org [mailto:gluster-users-bounces at gluster.org] Im
> > Auftrag von Sheng Yeo
> > Gesendet: Dienstag, 20. Juli 2010 00:39
> > An: gluster-users at gluster.org
> > Betreff: [Gluster-users] Slow speed with Gluster Backed Xen DomU's
> > 
> > Hi Everyone,
> > 
> > Hope your day has been going well. I tried emailing this in a week or so ago, but i do
> > not think that it got emailed to the group. I am just trying again, but apologies in
> > advanced if you have already read this.
> > I am currently using GlusterFS as a distributed SAN backend for the Xen based cloud
> > platform we are developing.
> > 
> > We deploy Xen virtuals on pairs of servers using GlusterFs V3 in replicate mode on
> > Debian Stable (Lenny) with Xen 3.2.1 as the hypervisor. I am currently experiencing a
> > weird issue where within the virtual machines (DomU) running on a GlusterFS mount
> > only receive around 10-18MB/s write speeds, but full speed reads.
> > 
> > Our hardware for each node is Dual Core Xeon Processors, 8GB of RAM and 4 * High
> > Speed SATA drives (RAID 10, around 160MB/s writes and reads).
> > 
> > If I write a file to the Gluster mount in the Dom0 (host) we receive around 90-100MB/s
> > writes (maxing out the GigE link). If I run the virtual machine on the disks without Gluster
> > I get much higher speeds within the DomU of around 80-90MB/s.
> > 
> > This slow down only appears to occur on writes. Does anyone with a better
> > understanding of GlusterFS, Fuse and filesystems have an idea why this is slowing
> > down. The underlying file system is Ext3 using TAP:AIO within Xen to connect to a file
> > image based disk. This is without using gluster fuse client (what benefits does this
> > give?) and Gluster version 3.0.4.
> > 
> > Many Thanks
> > Sheng
> > 
> > Here is the current configuration of the servers in replicate:
> > 
> > Server:
> > 
> > volume posix
> >    type storage/posix
> >    option directory /export
> > end-volume
> > 
> > volume locks
> >    type features/locks
> >    subvolumes posix
> > end-volume
> > 
> > volume brick
> >    type performance/io-threads
> >    option thread-count 8
> >    subvolumes locks
> > end-volume
> > 
> > volume server
> >    type protocol/server
> >    option transport-type tcp
> >    option auth.addr.brick.allow 10.*.*.*
> >    subvolumes brick
> > end-volume
> > 
> > Client:
> > 
> > volume remote1
> >    type protocol/client
> >    option transport-type tcp
> >    option remote-host node01
> >    option remote-subvolume brick
> > end-volume
> > 
> > volume remote2
> >    type protocol/client
> >    option transport-type tcp
> >    option remote-host node02
> >    option remote-subvolume brick
> > end-volume
> > 
> > volume replicate1
> >    type cluster/replicate
> >    subvolumes remote1 remote2
> > end-volume
> > 
> > 
> > volume writebehind
> >    type performance/write-behind
> >    option window-size 1MB
> >    subvolumes replicate1
> > end-volume
> > 
> > volume cache
> >    type performance/io-cache
> >    option cache-size 512MB
> >    subvolumes writebehind
> > end-volume
> > 
> 
> 
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> 
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