Hello everyone,
We have a problem in a 3 member OCFS2 cluster used to serve an web/php
application that access (read and/or write) files located in the OCFS2
volume.
The problem appears only some times (apparently during high load periods).
SYMPTOMS:
- access to OCFS2 content becomes more an more slow until stalls
* a "ls" command that normally takes <=1s takes 30s, 40s, 1m,...
- load average of the system grows to 150, 200 or even more
- high iowait values: 70-90%
* but CPU usage is low
- in the syslog appears a lot of messages like:
(httpd,XXXXX,Y):ocfs2_rename:1474 ERROR: status = -13
or
(httpd,XXXXX,Y):ocfs2_unlink:951 ERROR: status = -2
and the more "worrying":
kernel: INFO: task httpd:3488 blocked for more than 120 seconds.
kernel: "echo 0 > /proc/sys/kernel/hung_task_timeout_secs"
disables this message.
kernel: httpd D c6fe5d74 0 3488 1616 0x00000080
kernel: c6fe5e04 00000082 00000000 c6fe5d74 c6fe5d74 000041fd
c6fe5d88 c0439b18
kernel: c0b976c0 c0b976c0 c0b976c0 c0b976c0 ed0f0ac0 c6fe5de8
c0b976c0 f75ac6c0
kernel: f2f0cd60 c0a95060 00000001 c6fe5dbc c0874b8d c6fe5de8
f8fd9a86 00000001
kernel: Call Trace:
kernel: [<c0439b18>] ? default_spin_lock_flags+0x8/0x10
kernel: [<c0874b8d>] ? _raw_spin_lock+0xd/0x10
kernel: [<f8fd9a86>] ? ocfs2_dentry_revalidate+0xc6/0x2d0 [ocfs2]
kernel: [<f8ff17be>] ? ocfs2_permission+0xfe/0x110 [ocfs2]
kernel: [<f905b6f0>] ? ocfs2_acl_chmod+0xd0/0xd0 [ocfs2]
kernel: [<c0873105>] schedule+0x35/0x50
kernel: [<c0873b2e>] __mutex_lock_slowpath+0xbe/0x120
....
(UNACCEPTABLE) WORKAROUND:
stop httpd (really slow)
stop ocfs2 service (really slow)
start ocfs2 an httpd
MORE INFO:
- OS information:
Oracle Linux 6.4 32bit
4GB RAM
uname -a: 2.6.39-400.109.6.el6uek.i686 #1 SMP Wed Aug 28 09:55:10
PDT 2013 i686 i686 i386 GNU/Linux
* anyway: we have another 5 nodes cluster with Oracle Linux 7.1 (so
64bit OS) serving a newer version of the same application and the
problems are similar, so it appears not to be a OS problem but a more
specific OCFS2 problem (bug? some tuning? other?)
- standard configuration
* if you want I can show the cluster.conf configuration but is the
"expected configuration"
- standard configuration in o2cb:
Driver for "configfs": Loaded
Filesystem "configfs": Mounted
Stack glue driver: Loaded
Stack plugin "o2cb": Loaded
Driver for "ocfs2_dlmfs": Loaded
Filesystem "ocfs2_dlmfs": Mounted
Checking O2CB cluster "MoodleOCFS2": Online
Heartbeat dead threshold: 31
Network idle timeout: 30000
Network keepalive delay: 2000
Network reconnect delay: 2000
Heartbeat mode: Local
Checking O2CB heartbeat: Active
- mount options: _netdev,rw,noatime
* so other options (commit, data, ...) have their default values
Any ideas/suggestion?
Regards.
--
------------------------------------------------------------------------
*Area de Sistemas
Servicio de las Tecnologias de la Informacion y Comunicaciones (STIC)
Universidad de Valladolid
Edificio Alfonso VIII, C/Real de Burgos s/n. 47011, Valladolid - ESPAÑA
Telefono: 983 18-6410, Fax: 983 423271
E-mail: siste...@uva.es
*
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