Use the following tools to troubleshoot OCFS2 issues:

• Install netconsole on the nodes to capture an oops trace.

• Use the tcpdump command to capture the DLM's network traffic between nodes. For example, to capture TCP traffic on port 7777 for the private network interface em2, you could use the following command:

  sudo tcpdump -i em2 -C 10 -W 15 -s 10000 -Sw /tmp/`hostname -s`_tcpdump.log \
  -ttt 'port 7777' &

• Use the debugfs.ocfs2 command to trace events in the OCFS2 driver, view the status of locks, walk directory structures, examine inodes, and so on. This command is similar in behavior to the debugfs command that's used for the ext3 file system.

  For more information, see the debugfs.ocfs2(8) manual page.

• Use the o2image command to save an OCFS2 file system's metadata, including information about inodes, file names, and directory names, to an image file on another file system. Because the image file contains only metadata, it's much smaller than the original file system. You can use the debugfs.ocfs2 command to open the image file and analyze the file system layout to discover the cause of a file system corruption or performance problem.

  For example, to create the image /tmp/sda2.img from the OCFS2 file system on the device /dev/sda2, you would use the following command:

  sudo o2image /dev/sda2 /tmp/sda2.img

  For more information, see the o2image(8) manual page.