Running TOMCAT on z/OS 1.4 and would like to know if there is a recommended value for the ASSIZEMAX that should be assigned as part of the OMVS segment that the TOMCAT started task userid uses.
Cheers,
Roger
What ASSIZEMAX value should be used?
I believe that ASSIZEMAX would only apply if you are running the Java JVM under an OMVS address space. Running under the JZOS batch launcher, your JVM is running under a regular batch initiator or started task address space.
For a started task, I think that REGION= on the EXEC PGM= statement controls the maxassize (although system parameters and exits might affect this as well). You can check what you are actually getting by running the batch launcher with LOGLVL=+I or +T, which will write a message at startup that displays the storage limits of the address space.
The amount of memory that is required depends on which JDK you are using; JDK 1.4 requires significantly more memory. The JDK 1.4.2 Diagnostics Guide, chapter 19, says that 140MB of total private area storage is sufficient for the default JVM maximum heap size of 64MB. A 64MB heap would be plenty for many Tomcat servers, but your applications requirements might differ.
I usually just specify REGION=0M and then set the max heap size to what I need, e.g -Xmx128m
For a started task, I think that REGION= on the EXEC PGM= statement controls the maxassize (although system parameters and exits might affect this as well). You can check what you are actually getting by running the batch launcher with LOGLVL=+I or +T, which will write a message at startup that displays the storage limits of the address space.
The amount of memory that is required depends on which JDK you are using; JDK 1.4 requires significantly more memory. The JDK 1.4.2 Diagnostics Guide, chapter 19, says that 140MB of total private area storage is sufficient for the default JVM maximum heap size of 64MB. A 64MB heap would be plenty for many Tomcat servers, but your applications requirements might differ.
I usually just specify REGION=0M and then set the max heap size to what I need, e.g -Xmx128m