[Linux-cluster] performance on a 4 node cluster after 6/7 days
Support @ Sylconia
hosting at sylconia.nl
Tue Jan 9 17:59:39 UTC 2007
Dear reader,
short version:
we are experiencing performance problems after 6/7 days of running time on the non lock master(s).
long version:
We have the following setup:
a 4 node RHCS cluster where node 4 (backend) exports 3 raid disks via gnbd to the other nodes (1-3)
The other 3 nodes (frontend) import those exports via gnbd. We have created 4 LV's via clvmd on top of those imported disks.
logical volumes
/dev/mapper/vg0-tmp 9.7G 1.1M 9.7G 1% /phpsessions
/dev/mapper/vg0-config 9.7G 152K 9.7G 1% /config
/dev/mapper/vg0-logging 100G 126M 100G 1% /var/log/httpd
/dev/mapper/vg0-www 500G 222M 500G 1% /www
as lock manager we use lock_dlm with following rpm's installed
dlm-kernel-2.6.9-44.3
dlm-1.0.1-1
gfs version
gfs_tool -V
gfs_tool 6.1.6 (built Aug 25 2006 15:17:50)
gnbd version
Copyright (C) Red Hat, Inc. 2004-2005 All rights reserved.
gnbd_import 1.0.8. (built Nov 14 2006 02:18:52)
Copyright (C) Red Hat, Inc. 2004 All rights reserved.
cman_tool status
Protocol version: 5.0.1
os version centos 4.4 on all nodes
all rpm's are from the centos.org website.
all nodes are connected via a seperate NIC (GB) and private gigabit VLAN no other network traffic is on this VLAN.
Now this is all running fine till 6 or 7 days running time than the nodes which are not lock master are becoming very slow in for example a df command. while df runs the cpu load rises to 4 or 5 and the node is not very responsive (it seems the os hangs for a few seconds)
Running the top command at the same time shows
18524 root 15 -10 0 0 0 R 97.4 0.0 1:08.99 dlm_sendd
12959 root 18 0 4184 592 528 R 1.9 0.1 0:00.17 df
so i think the problem is in dlm but i do not know how to debug this can someone give me some pointers? I checked /proc/cluster/dlm* but honestly do not know what to look for.
regards
Constan
Sylconia.nl
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