When a reserve file group is opened by the jnlopnfg command, it becomes a standby file group.

When an overwritable file group is closed by the jnlclsfg command, it becomes a reserve file group. A non-overwritable file group cannot be closed, because it contains a journal required for recovery.

If there is only one overwritable file group, that file group cannot be closed.

The following figure shows the status changes for a system journal file caused by the open and close commands.

Figure 4-7 Status changes caused by open and close commands (system journal file)