[Gluster-users] glusterfs and glusterfsd process utilization extremely high

[Pranith Kumar Karampuri]

On 11/22/2014 10:40 PM, Pranith Kumar Karampuri wrote:
>
> On 11/22/2014 10:29 PM, Kyle Harris wrote:
>> Hello,
>>
>> I have an issue with a 3 node replicated cluster.  My issue started 
>> after reboot a while back.  The top command would show the glusterfs 
>> and glusterfsd processes eating up almost all the resources on an all 
>> three nodes of the cluster.  So much so that it would not run the web 
>> sites that are hosted on it.  The httpd processes would begin to 
>> hang.  I finally decided to tear down the cluster and rebuild it from 
>> the ground up.  I did so and then copied all the data back which took 
>> all night due to the amount of data.  All was well during that entire 
>> copy process back to the cluster with no resource spikes.
Assuming you go back to 3.5.2
Execute the following commands:
# gluster volume set <volname> cluster.entry-self-heal off

This should prevent httpd hangs.

If you still find that the CPU usage is very high, execute the following 
command:
# gluster volume set <volname> cluster.self-heal-daemon off

This disables self-healing. But you should probably periodically heal so 
that the data is healed by enabling self-heal-daemon using following 
command:
# gluster volume set <volname> cluster.self-heal-daemon on

Once "gluster volume heal <volname> info" shows zero entries, then 
healing is complete.

We took some steps to improve this in 3.6. But readdir in EXT4 is not 
working correctly so that is probably giving problems here. Lets wait 
for Vijay to merge the patch I mentioned, then things should be fine.

Pranith
>>
>> I should note that this cluster is home to many Apache/PHP based web 
>> sites.  The problem starts again, however the minute I point traffic 
>> back to the sites on the cluster.  Before pointing traffic to it, all 
>> is fine but as soon as the traffic begins to hit it, the utilization 
>> again begins to spike.  Note that all the sites run just fine when 
>> hosted from a standard EXT4 partition.  I noticed another thread 
>> labeled "glusterfsd process thrashing CPU" where Pranith asks if the 
>> user has directories with lots of files and I do.
>>
>> Here are some other details of my cluster:
>> - OS:  CentOS 6.6 with all updates on all 3 nodes as of 11-22-2014
>> - All 3 nodes have 8 cores with 16 GB of RAM
>> - Nodes are all formatted with EXT4
>> - All three nodes also have the files systems mounted on them for use 
>> with Apache.  I have experimented with both NFS and Fuse mounts and 
>> it doesn't seem to make a difference which I use for this particular 
>> problem.  I am currently using Fuse.
>> - Approximately 135 GB of data.  Some deep directories with many 
>> small files.
>> - No optimization or changes have been made to the cluster . . . it 
>> is running with default options
>> - Gluster version 3.6.1-1 installed from RPMs
>> - Note the issue originally occurred on version 3.5.2 but I updated 
>> before rebuilding it in hopes that would fix it (it didn't)
>>
>> Can anyone give me guidance on how to tackle this problem?  I am 
>> hoping perhaps Pranith can give some details as to why the question 
>> about many files and how to proceed given my situation.  I know 
>> others have commented about having many small files with regard to 
>> performance but when the processors are not spiked, performance has 
>> been acceptable.  Any help would be greatly appreciated.
>>
> Kyle,
>       3.6.1 and EXT4 has a problem because of 64 bits offset. Afr-v2 
> implementation introduced this problem. We thought the following patch 
> is merged but it didn't :-( http://review.gluster.com/8201. Please 
> don't use 3.6.1 with EXT4
>
> Vijay,
>       Please merge http://review.gluster.com/8201
>
> Pranith
>> -- 
>> Kyle
>>
>>
>>
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>

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