n is an integer in the range 0—1,000,000 (MB). The default value is 0.
MaxIRISTempSizeAtStart is the maximum physical size in megabytes of the IRISTEMP database during instance startup. When the instance restarts, InterSystems IRIS® data platform truncates the IRISTEMP database to the size that MaxIRISTempSizeAtStart specifies. If this parameter is set to 0, the IRISTEMP database is not truncated on instance restart.
InterSystems IRIS initializes a maximum of 240 MB in the IRISTEMP database at instance startup. This may be significantly less than the physical size of the database’s IRIS.DAT file.
Changing This Parameter
On the Startup page of the Management Portal (System Administration > Configuration > Additional Settings > Startup), in the MaxIRISTempSizeAtStart row, select Edit. Enter a number of megabytes.
Instead of using the Management Portal, you can change MaxIRISTempSizeAtStart in the Config.Startup 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).