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Re: [Linux-cluster] GFS performance issue on CentOS 5.5



 Does manually tuning glock trimming still apply to GFS2?

I have seen references that have talked about increasing resource
groups, and also resources saying that if increased to high it could
hurt performance.  From what I can figure out looks like the only way to
change this is a reformat, is this correct?  I am not opposed to doing
this, as this cluster is not yet in production, although, reformating,
and restoring all the content to the file system will take a pretty
decent amount of time, so I don't really want to do it to many times. 
Would increasing the resource groups be a worth while thing to try, and
if so, is there any good way to figure out (short of trial and error)
what value I should use for the resource group allocation?

I found this tread from a search using a search links I found in one of
the threads you gave me a link to:
http://www.mail-archive.com/linux-cluster redhat com/msg00990.html

On 7/23/2010 11:15 AM, Gordan Bobic wrote:
> Sounds like you are suffering from extreme lock bouncing between the
> nodes. This is a FAQ. I suggest you have a read through the mail
> archives of this list for similar discussions, e.g.:
>
> http://www.mail-archive.com/linux-cluster redhat com/msg04412.html
> http://www.mail-archive.com/linux-cluster redhat com/msg08177.html
>
> Gordan
>
> On Thu, 2010-07-22 at 11:55 -0400, Fred Wittekind wrote:
>> Two web servers, both virtualized with CentOS Xen servers as host
>> (residing on two different physical servers). 
>> GFS used to store home directories containing web document roots.
>>
>> Shared block device used by GFS is an ISCSI target with the ISCSI
>> initiator residing on the Dom-0, and presented to Dom-U webservers as
>> drives.
>> Also, providing a second shared block device for quorum disk.
>>
>> If I hit the web site on just one of the nodes, it behaves as expected. 
>> If I try to load the websites from both nodes at the same time (two web
>> browser instances), the load average on both nodes spikes, and page
>> loads very slowly.  The site I am trying to host is very high traffic,
>> and if the servers can be nearly brought to there knees with two web
>> browser instances running on a single workstation, that's not going to work.
>>
>> I am not seeing any error messages in the logs regarding the cluster.
>>
>> Any help or suggestions on how to troubleshoot this issue would be
>> greatly appreciated.
>>
>>
>> [root www3 www]# find ./ | wc -l
>> 64815
>>
>> [root www3 www]# gfs2_tool df /home/www
>> /home/www:
>>   SB lock proto = "lock_dlm"
>>   SB lock table = "Web:homewww"
>>   SB ondisk format = 1801
>>   SB multihost format = 1900
>>   Block size = 4096
>>   Journals = 2
>>   Resource Groups = 316
>>   Mounted lock proto = "lock_dlm"
>>   Mounted lock table = "Web:homewww"
>>   Mounted host data = "jid=1:id=393217:first=0"
>>   Journal number = 1
>>   Lock module flags = 0
>>   Local flocks = FALSE
>>   Local caching = FALSE
>>
>>   Type           Total Blocks   Used Blocks    Free Blocks    use%
>>   ------------------------------------------------------------------------
>>   data           20707148       4347237        16359911       21%
>>   inodes         16426386       66475          16359911       0%
>>
>> [root www3 www]# gfs2_tool gettune /home/www
>> new_files_directio = 0
>> new_files_jdata = 0
>> quota_scale = 1.0000   (1, 1)
>> logd_secs = 1
>> recoverd_secs = 60
>> statfs_quantum = 30
>> stall_secs = 600
>> quota_cache_secs = 300
>> quota_simul_sync = 64
>> statfs_slow = 0
>> complain_secs = 10
>> max_readahead = 262144
>> quota_quantum = 60
>> quota_warn_period = 10
>> jindex_refresh_secs = 60
>> log_flush_secs = 60
>> incore_log_blocks = 1024
>>
>> [root www3 www]# cat /etc/cluster/cluster.conf |egrep '(dlm)|(gfs)'
>>         <dlm plock_ownership="1" plock_rate_limit="0"/>
>>         <gfs_controld plock_rate_limit="0"/>
>>
>>
>> Fred Wittekind
>>
>> --
>> Linux-cluster mailing list
>> Linux-cluster redhat com
>> https://www.redhat.com/mailman/listinfo/linux-cluster
>
> --
> Linux-cluster mailing list
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> https://www.redhat.com/mailman/listinfo/linux-cluster
>


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