[Gluster-users] high CPU load on all bricks

Michael Colonno mcolonno at stanford.edu
Sun Feb 3 19:22:38 UTC 2013

            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. 


            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. 



~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. 



            ~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. 



            ~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). 



            ~Mike C. 



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