n is either 1 or 0. The default value is 0.
When FreezeOnError is enabled (n = 1), then on a journal file I/O error, the Journal daemon freezes journaling immediately. The Journal daemon unfreezes journaling after it succeeds with the failed I/O operation. As soon as the error occurs all global activities that are normally journaled are blocked, which causes other jobs to hang; typically until you resolve the journaling problem. While InterSystems IRIS is hanging, you can take corrective measures, such as freeing up space on a full disk or switching the journal to a new working disk. This prevents the loss of journal data at the expense of system availability.
When FreezeOnError is not enabled, If FreezeOnError=0 (false), then InterSystems IRIS does not freeze on a journal file I/O error. InterSystems IRIS disables journaling if it is not able to recover in a timely manner from the error. This prevents the system from hanging. Journaling is first retried, and then disabled, while InterSystems IRIS continues running. If journaling is disabled, you want to backup your databases as soon as possible. Running without journaling is a calculated risk, as it means the activity that occurs during this period cannot be restored. If Journaling is disabled, you MUST restart it. Ways to restart it include running the ^JRNSTART routine or selecting option 1, Begin Journaling, from the ^JOURNAL routine menu. See the “Start Journaling Using ^JRNSTART” section for details.
For details, see the section “Journal I/O Errors” in the “Journaling” chapter in Data Integrity Guide.
Changing This Parameter
On the Journal Settings page of the Management Portal (System Administration > Configuration > System Configuration > Journal Settings), select FreezeOnError to enable this setting.
Instead of using the Management Portal, you can change PreezeOnError in the Config.Journal class (as described in the class reference) or by editing the CPF in a text editor (as described in the Editing the Active CPF section of the “Introduction to the Configuration Parameter File” chapter in this book).