[Gluster-users] high CPU load on all bricks
Michael Colonno
mcolonno at stanford.edu
Thu Feb 14 21:08:22 UTC 2013
Ok, good - I had that right. In that case the bricks each need to mount the volume. I mounted the volume on each brick to itself (localhost) so they would not depend on each other re: mounting.
But I am back to square one on the high CPU load / slow write speed issue. I'll try a test volume with a single node as brick and client to try any rule out anything network-related, though my network is performing well in every other way.
Thanks,
Mike C.
On Feb 14, 2013, at 12:31 PM, Bryan Whitehead <driver at megahappy.net> wrote:
> Yea, only write to the glusterfs mountpoint. Writing directly to the bricks is bad and shouldn't be done.
>
>
> On Thu, Feb 14, 2013 at 11:58 AM, Michael Colonno <mcolonno at stanford.edu> wrote:
>> Good place to start: do the bricks have to be clients as well? In other words if I copy a file to a Gluster brick without going through a glusterfs or NFS mount will that disrupt the parallel file system? I assumed files need to be routed through a glusterfs mount point for Gluster to be able to track them(?) What's recommended for bricks which also need i/o to the entire volume?
>>
>> Thanks,
>> Mike C.
>>
>> On Feb 14, 2013, at 10:28 AM, harry mangalam <harry.mangalam at uci.edu> wrote:
>>
>> > While I don't understand your 'each brick system also being a client' setup -
>> > you mean that each gluster brick is a native gluster client as well? And that
>> > is where much of your gluster access is coming from? That seems .. suboptimal
>> > if that's the setup. Is there a reason for that setup?
>> >
>> > We have a distributed-only glusterfs feeding a medium cluster over a similar
>> > same setup QDR IPoIB with 4 servers with 2 bricks each. On a fairly busy
>> > system (~80MB/s background), I can get about 100-300MB/s writes to the gluster
>> > fs on a large 1.7GB file. (With tiny writes, the perf decreases
>> > dramatically).
>> >
>> > Here is my config: (if anyone spies something that I should change to increase
>> > my perf, please feel free to point out my mistake)
>> >
>> > gluster:
>> > Volume Name: gl
>> > Type: Distribute
>> > Volume ID: 21f480f7-fc5a-4fd8-a084-3964634a9332
>> > Status: Started
>> > Number of Bricks: 8
>> > Transport-type: tcp,rdma
>> > Bricks:
>> > Brick1: bs2:/raid1
>> > Brick2: bs2:/raid2
>> > Brick3: bs3:/raid1
>> > Brick4: bs3:/raid2
>> > Brick5: bs4:/raid1
>> > Brick6: bs4:/raid2
>> > Brick7: bs1:/raid1
>> > Brick8: bs1:/raid2
>> > Options Reconfigured:
>> > performance.write-behind-window-size: 1024MB
>> > performance.flush-behind: on
>> > performance.cache-size: 268435456
>> > nfs.disable: on
>> > performance.io-cache: on
>> > performance.quick-read: on
>> > performance.io-thread-count: 64
>> > auth.allow: 10.2.*.*,10.1.*.*
>> >
>> > my RAID6s (via 3ware 9750s) are mounted with the following options
>> >
>> > /dev/sdc /raid1 xfs rw,noatime,sunit=512,swidth=8192,allocsize=32m 0 0
>> > /dev/sdd /raid2 xfs rw,noatime,sunit=512,swidth=7680,allocsize=32m 0 0
>> > (and should probably be using 'nobarrier,inode64' as well. - testing this now)
>> >
>> > There are some good refs on prepping XFS fs for max perf here:
>> > <http://www.mythtv.org/wiki/Optimizing_Performance#XFS-Specific_Tips>
>> > The script at:
>> > <http://www.mythtv.org/wiki/Optimizing_Performance#Further_Information>
>> > can help to setup the sunit/swidth options.
>> > <http://www.mysqlperformanceblog.com/2011/12/16/setting-up-xfs-the-simple-
>> > edition/>
>> > Your ib interfaces should be using large mtus (65536)
>> >
>> > hjm
>> >
>> > On Wednesday, February 13, 2013 10:35:12 PM Michael Colonno wrote:
>> >> More data: I got the Infiniband network (QDR) working well and
>> >> switched my gluster volume to the Infiniband fabric (IPoIB, not RDMA since
>> >> it doesn't seem to be supported yet for 3.x). The filesystem was slightly
>> >> faster but still well short of what I would expect by a wide margin. Via an
>> >> informal test (timing the movement of a large file) I'm getting several MB/s
>> >> - well short of even a standard Gb network copy. With the faster network
>> >> the CPU load on the brick systems increased dramatically: now I'm seeing
>> >> 200%-250% usage by glusterfsd and glusterfs.
>> >>
>> >> This leads me to believe that gluster is really not enjoying my
>> >> eight-brick, 2x replication volume with each brick system also being a
>> >> client. I tried a rebalance but no measurable effect. Any suggestions for
>> >> improving the performance? Having each brick be a client of itself seemed
>> >> the most logical choice to remove interdependencies but now I'm doubting the
>> >> setup.
>> >>
>> >>
>> >>
>> >> Thanks,
>> >>
>> >> ~Mike C.
>> >>
>> >>
>> >>
>> >> From: gluster-users-bounces at gluster.org
>> >> [mailto:gluster-users-bounces at gluster.org] On Behalf Of Joe Julian
>> >> Sent: Sunday, February 03, 2013 11:47 AM
>> >> To: gluster-users at gluster.org
>> >> Subject: Re: [Gluster-users] high CPU load on all bricks
>> >>
>> >>
>> >>
>> >> On 02/03/2013 11:22 AM, Michael Colonno wrote:
>> >>
>> >>
>> >>
>> >> Having taken a lot more data it does seem the glusterfsd and
>> >> glusterd processes (along with several ksoftirqd) spike up to near 100% on
>> >> both client and brick servers during any file transport across the mount.
>> >> Thankfully this is short-lived for the most part but I'm wondering if this
>> >> is expected behavior or what others have experienced(?) I'm a little
>> >> surprised such a large CPU load would be required to move small files and /
>> >> or use an application within a Gluster mount point.
>> >>
>> >>
>> >> If you're getting ksoftirqd spikes, that sounds like a hardware issue to me.
>> >> I never see huge spikes like that on my servers nor clients.
>> >>
>> >>
>> >>
>> >>
>> >>
>> >>
>> >> I wanted to test this against an NFS mount of the same Gluster
>> >> volume. I managed to get rstatd installed and running but my attempts to
>> >> mount the volume via NFS are met with:
>> >>
>> >>
>> >>
>> >> mount.nfs: requested NFS version or transport protocol is not
>> >> supported
>> >>
>> >>
>> >>
>> >> Relevant line in /etc/fstab:
>> >>
>> >>
>> >>
>> >> node1:/volume /volume nfs
>> >> defaults,_netdev,vers=3,mountproto=tcp 0 0
>> >>
>> >>
>> >>
>> >> It looks like CentOS 6.x has NFS version 4 built into everything. So a few
>> >> questions:
>> >>
>> >>
>> >>
>> >> - Has anyone else noted significant performance differences between a
>> >> glusterfs mount and NFS mount for volumes of 8+ bricks?
>> >>
>> >> - Is there a straightforward way to make the newer versions of CentOS
>> >> play nice with NFS version 3 + Gluster?
>> >>
>> >> - Are there any general performance tuning guidelines I can follow to
>> >> improve CPU performance? I found a few references to the cache settings but
>> >> nothing solid.
>> >>
>> >>
>> >>
>> >> If the consensus is that NFS will not gain anything then I won't waste the
>> >> time setting it all up.
>> >>
>> >>
>> >> NFS gains you the use of FSCache to cache directories and file stats making
>> >> directory listings faster, but it adds overhead decreasing the overall
>> >> throughput (from all the reports I've seen).
>> >>
>> >> I would suspect that you have the kernel nfs server running on your servers.
>> >> Make sure it's disabled.
>> >>
>> >>
>> >>
>> >>
>> >>
>> >>
>> >> Thanks,
>> >>
>> >> ~Mike C.
>> >>
>> >>
>> >>
>> >>
>> >>
>> >> From: gluster-users-bounces at gluster.org
>> >> [mailto:gluster-users-bounces at gluster.org] On Behalf Of Michael Colonno
>> >> Sent: Friday, February 01, 2013 4:46 PM
>> >> To: gluster-users at gluster.org
>> >> Subject: Re: [Gluster-users] high CPU load on all bricks
>> >>
>> >>
>> >>
>> >> Update: after a few hours the CPU usage seems to have dropped
>> >> down to a small value. I did not change anything with respect to the
>> >> configuration or unmount / stop anything as I wanted to see if this would
>> >> persist for a long period of time. Both the client and the self-mounted
>> >> bricks are now showing CPU < 1% (as reported by top). Prior to the larger
>> >> CPU loads I installed a bunch of software into the volume (~ 5 GB total). Is
>> >> this kind a transient behavior - by which I mean larger CPU loads after a
>> >> lot of filesystem activity in short time - typical? This is not a problem
>> >> in my deployment; I just want to know what to expect in the future and to
>> >> complete this thread for future users. If this is expected behavior we can
>> >> wrap up this thread. If not then I'll do more digging into the logs on the
>> >> client and brick sides.
>> >>
>> >>
>> >>
>> >> Thanks,
>> >>
>> >> ~Mike C.
>> >>
>> >>
>> >>
>> >> From: Joe Julian [mailto:joe at julianfamily.org]
>> >> Sent: Friday, February 01, 2013 2:08 PM
>> >> To: Michael Colonno; gluster-users at gluster.org
>> >> Subject: Re: [Gluster-users] high CPU load on all bricks
>> >>
>> >>
>> >>
>> >> Check the client log(s).
>> >>
>> >> Michael Colonno <mcolonno at stanford.edu> wrote:
>> >>
>> >> Forgot to mention: on a client system (not a brick) the
>> >> glusterfs process is consuming ~ 68% CPU continuously. This is a much less
>> >> powerful desktop system so the CPU load can't be compared 1:1 with the
>> >> systems comprising the bricks but still very high. So the issue seems to
>> >> exist with both glusterfsd and glusterfs processes.
>> >>
>> >>
>> >>
>> >> Thanks,
>> >>
>> >> ~Mike C.
>> >>
>> >>
>> >>
>> >> From: gluster-users-bounces at gluster.org
>> >> [mailto:gluster-users-bounces at gluster.org] On Behalf Of Michael Colonno
>> >> Sent: Friday, February 01, 2013 12:46 PM
>> >> To: gluster-users at gluster.org
>> >> Subject: [Gluster-users] high CPU load on all bricks
>> >>
>> >>
>> >>
>> >> Gluster gurus ~
>> >>
>> >>
>> >>
>> >> I've deployed and 8-brick (2x replicate) Gluster 3.3.1 volume on
>> >> CentOS 6.3 with tcp transport. I was able to build, start, mount, and use
>> >> the volume. On each system contributing a brick, however, my CPU usage
>> >> (glusterfsd) is hovering around 20% (virtually zero memory usage
>> >> thankfully). These are brand new, fairly beefy servers so 20% CPU load is
>> >> quite a bit. The deployment is pretty plain with each brick mounting the
>> >> volume to itself via a glusterfs mount. I assume this type of CPU usage is
>> >> atypically high; is there anything I can do to investigate what's soaking up
>> >> CPU and minimize it? Total usable volume size is only about 22 TB (about 45
>> >> TB total with 2x replicate).
>> >>
>> >>
>> >>
>> >> Thanks,
>> >>
>> >> ~Mike C.
>> >>
>> >>
>> >>
>> >>
>> >> _____
>> >>
>> >>
>> >> Gluster-users mailing list
>> >> Gluster-users at gluster.org
>> >> http://supercolony.gluster.org/mailman/listinfo/gluster-users
>> >>
>> >>
>> >>
>> >>
>> >>
>> >>
>> >> _______________________________________________
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>> >> Gluster-users at gluster.org
>> >> http://supercolony.gluster.org/mailman/listinfo/gluster-users
>> >
>> > ---
>> > Harry Mangalam - Research Computing, OIT, Rm 225 MSTB, UC Irvine
>> > [m/c 2225] / 92697 Google Voice Multiplexer: (949) 478-4487
>> > 415 South Circle View Dr, Irvine, CA, 92697 [shipping]
>> > MSTB Lat/Long: (33.642025,-117.844414) (paste into Google Maps)
>> > ---
>> > "Something must be done. [X] is something. Therefore, we must do it."
>> > Bruce Schneier, on American response to just about anything.
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>
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