[Linux-cluster] GFS performance issue on CentOS 5.5
Fred Wittekind
rom at twister.dyndns.org
Fri Jul 23 17:52:32 UTC 2010
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 at www3 www]# find ./ | wc -l
>> 64815
>>
>> [root at 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 at 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 at 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
>>
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>> Linux-cluster at redhat.com
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>
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