What is OCFS2?
- OCFS2 is a shared-disk cluster file system for Linux
- Capable of providing both high performance and high availability.
- Cluster-aware applications can make use of parallel I/O for higher performance with this FS
- OCFS2 is mostly used to host Oracle Real application clusters (RAC) database on Linux clusters.
The below are the high level steps for creating ocfs2 filesystem on top of a multipath'd SAN LUN:
- Verify the nodes that will be part of your cluster.
- Make sure your LUNs on the SAN end are accessible on all the nodes of the cluster.
- If you need multipathing, configure multipath and the multipathing policy based on solution whatever you have.
- The following example configuration ( /etc/ocfs2/cluster.conf ) shows you a sample configuration of a 2 node cluster pool.
- If you have heartbeat IP configured on these cluster nodes, use the heartbeat IP for ocfs2 cluster communication and specify the hostname without FQDN.
- Copy the same file to all the hosts in the cluster.
Sample Config file:
[root@rac-cluster ~]# cat /etc/ocfs2/cluster.conf
node:
ip_port = 7777
ip_address = 192.168.1.2
number = 0
name = rac-cluster
cluster = ocfs2
node:
ip_port = 7777
ip_address = 192.168.1.3
number = 1
name = rac-cluster
cluster = ocfs2
On each node check the status of OCFS2 cluster service and stop "o2cb" if the service is already running.
# service o2cb status # service o2cb stop
On each node, load the OCFS2 module.
# service o2cb load
Make the OCFS2 service online on all the nodes.
# service o2cb online
Now your OCFS2 cluster is ready.
Format the SAN lun device from any one of the cluster node.
# mkfs.ocfs2 -b 4k -C 32k -L oraclerac /dev/emcpowera
Where,
-b : Block size
-C : Cluster size
-L : Label
Update /etc/fstab on all the nodes in the cluster with the mount point.
/dev/emcpowera /u01 ocfs2 _netdev 0 0
Mount the /u01
Enable ocfs and o2b service on boot
# chkconfig --level 345 o2cb on# chkconfig --level 345 ocfs2 on
The /u01 repository setup on a SAN Lun is done.
You can now configure Oracle RAC on this file System.
