FAQ Search Today's Posts Mark Forums Read
» Video Reviews

» Linux Archive

Linux-archive is a website aiming to archive linux email lists and to make them easily accessible for linux users/developers.


» Sponsor

» Partners

» Sponsor

Go Back   Linux Archive > CentOS > CentOS

 
 
LinkBack Thread Tools
 
Old 07-19-2010, 03:41 PM
Fred Wittekind
 
Default GFS performance issue

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
_______________________________________________
CentOS mailing list
CentOS@centos.org
http://lists.centos.org/mailman/listinfo/centos
 
Old 07-20-2010, 11:41 AM
Pasi Kärkkäinen
 
Default GFS performance issue

On Mon, Jul 19, 2010 at 11:41:07AM -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.
>

You might want to read linux-cluster mailinglist archives for
GFS performance tuning tips.

Make sure you modify (increase) at least the max lock rate.

-- Pasi

>
> [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
> _______________________________________________
> CentOS mailing list
> CentOS@centos.org
> http://lists.centos.org/mailman/listinfo/centos
_______________________________________________
CentOS mailing list
CentOS@centos.org
http://lists.centos.org/mailman/listinfo/centos
 

Thread Tools




All times are GMT. The time now is 12:56 AM.

VBulletin, Copyright ©2000 - 2014, Jelsoft Enterprises Ltd.
Content Relevant URLs by vBSEO ©2007, Crawlability, Inc.
Copyright ©2007 - 2008, www.linux-archive.org