Userdata directory

You can use the userdata directory to store persistent application status.

Each IBM® MQ queue manager has a dedicated filesystem for its persistent state, which includes both its queue data and recovery log. The filesystem includes a userdata directory that you can use to store persistent status information for your applications. See Directory content on Unix and Linux® Systems and Directory content on Windows systems.

The userdata directory can be useful in a number of situations, for example:

In RDQM configurations so that application information also moves when a queue manager fails over to another node (see Storing persistent application status).
For multi-instance queue managers so their application state is located with their queue manager data on the shared network filesystem.
More generally, where applications are configured queue manager services.

If you choose to store application state in the userdata directory, you must be aware that data written to this location might consume the available disk space allocated to the queue manager. You must ensure that sufficient disk space remains available for the queue manager to write queue data, logs, and other persistent state information.

The userdata directory has mqm user and group ownership, and it is world readable so users can access it without needing to be in the IBM MQ administrator group (that is, mqm). You cannot modify the permissions of the userdata directory, but you can create content in it with whatever ownership and permissions you require.