View source for Set up an Oracle Cluster File System

You want to start your clustering experiences with an Oracle Cluster File System. Here is how. This is an example using SUSE Linux 11.2. As shared storage we use an iscsi storage.

= Installation =
* [[set up an iscsi storage]]
* [[set up a KVM virtual machine|set up two KVM virtual machines]]
: We assume here they are named node1 and node2 and have the IP addresses 192.168.0.11 and 192.168.0.12.

* On both nodes, configure your iscsi initiator, install everything that yast proposes:
 yast2 iscsi-client

* On both nodes, install ocfs2 software
 yast -i ocfs2-tools ocfsconsole ocfs2-tools-o2cb

* On both nodes, make the cluster services start at boot
 chkconfig o2cb on
 /etc/init.d/o2cb enable
You get a message "cluster not known". That is okay.

* check that each node can reach each other
 node1:~ # ping node2
 PING node2 (192.168.0.12) 56(84) bytes of data.
 64 bytes from node2 (192.168.0.12): icmp_seq=1 ttl=64 time=1.09 ms

 node2:~ # ping node1
 PING node1 (192.168.0.11) 56(84) bytes of data.
 64 bytes from node1 (192.168.0.11): icmp_seq=1 ttl=64 time=1.09 ms

* Start ocfs2console 
** Choose Cluster->Configure Nodes...
** write the cluster nodes in with their local host names (what the command "hostname" returns).
** Choose Cluster->Propagate Configuration...

= TroubleShooting =

== Unable to access cluster service while trying to initialize cluster ==

=== Symptom ===
When trying to mount the cluster volume you get the error message
 node1:~ # mount /dev/sdb /mnt
 mount.ocfs2: Unable to access cluster service while trying initialize cluster

=== Reason ===
Once the reason was the cluster service had not been started on all nodes.

=== Solution ===
Start the cluster service on all nodes:
<pre>
node2:~ # /etc/init.d/o2cb status
Driver for "configfs": Not loaded
Driver for "ocfs2_dlmfs": Not loaded
node2:~ # /etc/init.d/o2cb enable
Writing O2CB configuration: OK
Loading filesystem "configfs": OK
Mounting configfs filesystem at /sys/kernel/config: OK
Loading stack plugin "o2cb": OK
Loading filesystem "ocfs2_dlmfs": OK
Mounting ocfs2_dlmfs filesystem at /dlm: OK
Cluster not known
node2:~ # /etc/init.d/o2cb status
Driver for "configfs": Loaded
Filesystem "configfs": Mounted
Stack glue driver: Loaded
Stack plugin "o2cb": Loaded
Driver for "ocfs2_dlmfs": Loaded
Filesystem "ocfs2_dlmfs": Mounted
</pre>

== Unable to access cluster service while creating node ==

=== Symptom ===
In ocfs2console when adding nodes you get the error message
 o2cb_ctl: Unable to access cluster service while creating node
 Could not add node '''node1'''

=== Solution 1 ===
The following solution worked once:
Delete /etc/ocfs2/cluster.conf
 rm /etc/ocfs2/cluster.conf

=== Solution 2 ===
The following solution worked once:
Write /etc/ocfs2/cluster.conf manually:
<pre>
node:
        name = node1
        cluster = ocfs2
        number = 0
        ip_address = 192.168.0.11
        ip_port = 7777

node:
        name = node2
        cluster = ocfs2
        number = 1
        ip_address = 192.168.0.12
        ip_port = 7777

cluster:
        name = ocfs2
        node_count = 2
</pre>

== you see files only on one node ==
=== Symptom ===
You have your filesystem mounted and add a file on one node, but do not see it on the other node.

=== Reason 1 ===
In one case the reason for this was that the user had forgotten to "propagate configuration" AND node2 could not be reached over the network.