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