Does the z/OSMF Configuration Assistant Provide a Locking Mechanism for Backing Store Files?

The z/OSMF Configuration Assistant for z/OS Communications Server has a locking mechanism to prevent the overwriting of backing store files.

When a backing store file is opened in the Configuration Assistant, a lock file is created that contains a lock ID value, and the date and time at which the lock file was created.

When you specify "Local or LAN DASD" as your preference, you can create a lock ID value of your own or use the host name of the workstation that is running the Configuration Assistant.

When you specify "z/OS DASD" as your preference, the lock ID value is the user ID that is used to establish the FTP connection.

For z/OSMF, the lock ID value is the z/OSMF logon user ID. If you open a backing store file and the lock is already held, you get a dialog panel. From this dialog, you can choose to continue the session with the data in read-only mode, select a different backing store file, or cancel. The dialog also shows the contents of the lock file, so you can determine who has the backing store file in read-write mode, and when they obtained the lock.

The lock is always obtained when a user opens the Configuration Assistant. If the user exits by using the Exit button, the lock is freed. Otherwise the lock is held to prevent 2 users from attempting to update the same configuration at the same time. If the user does not exit cleanly (for example just closes the browser in the middle of a session), then the lock is freed after the WAS (WebSphere Application Server) timeout limit is reached. However, if the same user logs in to Configuration Assistant from the same IP address and the lock is still held, the user is allowed to seamlessly retake the lock and proceed.