n is an integer. The default is 0.
When targwijsz is set, the WIJ expands to the specified size (in MB). The value is an integer, but fractional input is accepted and silently truncated (for example, 35.5 becomes 35).
If the WIJ is not large enough, InterSystems IRIS® data platform increases its size as needed (regardless of the value of targwijsz). The targwijsz parameter allows you to allocate space to the WIJ ahead of time so it does not need to grow during a period of high activity. While there is no upper limit for targwijsz, it is not useful to set it higher than the maximum size of the database cache, as that is the most space the WIJ needs.
For more information, see the Write Image Journaling and Recovery chapter in Data Integrity Guide.
Setting this target size ensures that disk space is allocated for the WIJ early in the start-up process. If sufficient space is not allocated early and there is not enough available space for the WIJ, the instance may encounter problems. Allocating space for WIJ is an advanced configuration setting. If you encounter issues with this, contact the InterSystems Worldwide Resource CenterOpens in a new window.
Changing This Parameter
On the Advanced Memory Settings page of the Management Portal (System Administration > Configuration > Additional Settings > Advanced Memory), click the Edit link in the targwijsz row. The Edit: targwijsz page provides details about the setting and allows you to change its value.
Instead of using the Management Portal, you can change targwijsz in the Config.configOpens in a new window 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).