[Gluster-users] Very slow roaming profiles on top of glusterfs

Fri Sep 25 23:08:43 UTC 2015

I am _pretty_sure_ its only 3.7+ based, IIRC on upstream anything 3.6 should work around it.  Lemme see if I can dig up the patch that fixed the issue that lead to this regression so we can be sure, but I would try the latest 3.6.  For Red Hat based distros go with 3.0.4(which has the MT epoll patch but no lookup optimize, both of which REALLY help smallfile perf).

-b

----- Original Message -----
> From: "Thibault Godouet" <tibo92 at godouet.net>
> To: "Ben Turner" <bturner at redhat.com>
> Cc: gluster-users at gluster.org
> Sent: Friday, September 25, 2015 11:43:55 AM
> Subject: Re: [Gluster-users] Very slow roaming profiles on top of glusterfs
> 
> Hi Ben,
> 
> Regarding https://bugzilla.redhat.com/show_bug.cgi?id=1250241which does
> look like a serious regression for small file performance, do you know
> which versions are affected, or is there a way to find out?
> 
> Also the patch didn't make it: do you have visibility on whether another
> patch is likely to land soon?
> 
> If not I may try the version before the regression was introduced...
> 
> Thanks,
> Thibault.
> On 14 Sep 2015 4:22 pm, "Ben Turner" <bturner at redhat.com> wrote:
> 
> > ----- Original Message -----
> > > From: "Diego Remolina" <dijuremo at gmail.com>
> > > To: "Alex Crow" <acrow at integrafin.co.uk>
> > > Cc: gluster-users at gluster.org
> > > Sent: Monday, September 14, 2015 9:26:17 AM
> > > Subject: Re: [Gluster-users] Very slow roaming profiles on top of
> > glusterfs
> > >
> > > Hi Alex,
> > >
> > > Thanks for the reply, I was aware of the performance issues with small
> > > files, but never expected an order of magnitude slower. I understand
> > > some improvements were made to 3.7.x to help with low small file
> > > performance, however I did not see any big changes after upgrading
> > > from 3.6.x to 3.7.x.
> > >
> > >
> > http://www.gluster.org/community/documentation/index.php/Features/Feature_Smallfile_Perf
> > >
> > > And the ssd metadata support feature seems to have not had any changes
> > > since September 2014:
> > >
> > > https://forge.gluster.org/gluster-meta-data-on-ssd
> > >
> > > Am I just totally out of luck with gluster for now?
> >
> > Are you using glusterFS mounts or SMB mounts?  As for SMB mounts we are
> > working VERY hard to improve metadata / smallfile performance but as it
> > sits right now we are limited by the number of lookup / stat calls that are
> > issued.  When we can reduce the number of lookups and prefetch the xattrs
> > that SMB / windows needs(I am working on the stat prefetch but don't have a
> > testable solution yet) I expect to see a vast perf improvement but I don't
> > have an ETA for you.
> >
> > On the glusterFS side I see ~300% improvement in smallfile create
> > performance between 3.6 and 3.7.  Try setting:
> >
> > gluster volume set testvol server.event-threads 4
> > gluster volume set testvol client.event-threads 4
> > gluster volume set testvol cluster.lookup-optimize on
> >
> > Unfortunately WRT to metadata operations a fix went in that has negatively
> > affected performance:
> >
> > https://bugzilla.redhat.com/show_bug.cgi?id=1250241
> >
> > I used to see about 25k metatdata operations per second, now I am only
> > seeking 6k.  It looks like there is a patch but I don't know if the fix
> > will get us back to the 25k OPs per second, maybe Pranith can comment on
> > expectations for:
> >
> > https://bugzilla.redhat.com/show_bug.cgi?id=1250803
> >
> > To summarize:
> >
> > SMB - no ETA for improvement
> > GlusterFS smallfile create - 300% increase in my env between 3.6 and 3.7
> > GlusterFS metadata - BZ is in POST(patch is submitted) but I am not sure
> > on the ETA of the fix and if the fix will get back to what I was seeing in
> > 3.6
> >
> > Hope this helps.
> >
> > -b
> >
> > >
> > > Diego
> > >
> > > On Mon, Sep 14, 2015 at 8:37 AM, Alex Crow <acrow at integrafin.co.uk>
> > wrote:
> > > > Hi Diego,
> > > >
> > > > I think it's the overhead of fstat() calls. Gluster keeps its metadata
> > on
> > > > the bricks themselves, and this has to be looked up for every file
> > access.
> > > > For big files this is not an issue as it only happens once, but when
> > > > accessing lots of small files this overhead rapidly builds up, the
> > smaller
> > > > the file the worse the issue. Profiles do have hundreds of very small
> > > > files!
> > > >
> > > > I was looking to use GlusterFS for generic file sharing as well, but I
> > > > noticed the same issue while testing backups from a GlusterFS volume.
> > On
> > > > one
> > > > vol (scanned 4-bit greyscale images and small PDFs) backups were taking
> > > > over
> > > > 16 hours whereas with a traditional FS they were completing in just
> > over 1
> > > > hour.
> > > >
> > > > It may be worth trying out one of the distributed filesystems that use
> > a
> > > > separate in-memory metadata server. I've tried LizardFS and MooseFS and
> > > > they
> > > > are both much faster than GlusterFS for small files, although
> > large-file
> > > > sequential performance is not as good (but still plenty for a Samba
> > > > server).
> > > >
> > > > Alex
> > > >
> > > >
> > > > On 14/09/15 13:21, Diego Remolina wrote:
> > > >>
> > > >> Bump...
> > > >>
> > > >> Anybody has any clues as to how I can try and identify the cause of
> > > >> the slowness?
> > > >>
> > > >> Diego
> > > >>
> > > >> On Wed, Sep 9, 2015 at 7:42 PM, Diego Remolina <dijuremo at gmail.com>
> > wrote:
> > > >>>
> > > >>> Hi,
> > > >>>
> > > >>> I am running two glusterfs servers as replicas. I have a 3rd server
> > > >>> which provides quorum. Since gluster was introduced, we have had an
> > > >>> issue where windows roaming profiles are extremely slow. The initial
> > > >>> setup was done on 3.6.x and since 3.7.x has small file performance
> > > >>> improvements, I upgraded to 3.7.3, but that has not helped.
> > > >>>
> > > >>> It seems that for some reason gluster is very slow when dealing with
> > > >>> lots of small files. I am not sure how to really troubleshoot this
> > via
> > > >>> samba, but I have come up with other tests that produce rather
> > > >>> disconcerting results as shown below.
> > > >>>
> > > >>> If I run directly on the brick:
> > > >>> [root at ysmha01 /]# time ( find
> > > >>> /bricks/hdds/brick/home/jgibbs/.winprofile.V2 -type f > /dev/null )
> > > >>> real 0m3.683s
> > > >>> user 0m0.042s
> > > >>> sys 0m0.154s
> > > >>>
> > > >>> Now running on the gluster volume mounted via fuse:
> > > >>> [root at ysmha01 /]# mount | grep export
> > > >>> 10.0.1.6:/export on /export type fuse.glusterfs
> > > >>> (rw,relatime,user_id=0,group_id=0,allow_other,max_read=131072)
> > > >>>
> > > >>> [root at ysmha01 /]# time ( find /export/home/jgibbs/.winprofile.V2
> > -type
> > > >>> f > /dev/null )
> > > >>> real 0m57.812s
> > > >>> user 0m0.118s
> > > >>> sys 0m0.374s
> > > >>>
> > > >>> In general, the time to run the command on this particular user can
> > be
> > > >>> up to 2 minutes. If I run the command on the brick first, then it
> > > >>> seems the time to run on the mounted gluster volume is lower like in
> > > >>> the example above. I assume some caching in preserved.
> > > >>>
> > > >>> This particular user has 13,216 files in his roaming profile, which
> > > >>> adds up to about 452MB of data.
> > > >>>
> > > >>> The server performance over samba for copying big files (both read
> > and
> > > >>> write) is great, I can almost max out the gigabit connections on the
> > > >>> desktops.
> > > >>>
> > > >>> Reading from samba share on the server and writing to local drive:
> > > >>> 111MB/s (Copying a 650MB iso file)
> > > >>> Reading from local drive and writing to server samba share: 94MB/s
> > > >>> (Copying a 3.2GB ISO file)
> > > >>>
> > > >>> The servers are connected to the network with 10Gbit adapters and
> > also
> > > >>> use separate adapters; one 10 Gbit adapter is used for services, and
> > > >>> other for the backend storage communication.
> > > >>>
> > > >>> The servers have hardware raid controllers and the samba shares are
> > on
> > > >>> top of an Areca ARC-1882 controller, with a volume made out of 12 2TB
> > > >>> drives in raid 6.
> > > >>>
> > > >>> If you can provide any steps to better troubleshoot this problem and
> > > >>> fix the issue, I will really appreciate it.
> > > >>>
> > > >>> Diego
> > > >>>
> > > >>> Further details about the machines below:
> > > >>>
> > > >>> [root at ysmha01 /]# cat /etc/redhat-release
> > > >>> CentOS Linux release 7.1.1503 (Core)
> > > >>>
> > > >>> [root at ysmha01 /]# gluster volume info export
> > > >>> Volume Name: export
> > > >>> Type: Replicate
> > > >>> Volume ID: b4353b3f-6ef6-4813-819a-8e85e5a95cff
> > > >>> Status: Started
> > > >>> Number of Bricks: 1 x 2 = 2
> > > >>> Transport-type: tcp
> > > >>> Bricks:
> > > >>> Brick1: 10.0.1.7:/bricks/hdds/brick
> > > >>> Brick2: 10.0.1.6:/bricks/hdds/brick
> > > >>> Options Reconfigured:
> > > >>> performance.io-cache: on
> > > >>> performance.io-thread-count: 64
> > > >>> nfs.disable: on
> > > >>> cluster.server-quorum-type: server
> > > >>> performance.cache-size: 1024MB
> > > >>> server.allow-insecure: on
> > > >>> cluster.server-quorum-ratio: 51%
> > > >>>
> > > >>> Each server has dual Intel(R) Xeon(R) CPU E5-2620 0 @ 2.00GHz with
> > > >>> 32GB of memory.
> > > >>
> > > >> _______________________________________________
> > > >> Gluster-users mailing list
> > > >> Gluster-users at gluster.org
> > > >> http://www.gluster.org/mailman/listinfo/gluster-users
> > > >
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