To avoid storage shortages, consider the following conditions:
- If a region size is specified, the bufhigh value
should not be more than 90 percent of the region size. (The more bufhigh; the better performance.) With bufhigh(4M) and the existing NFS core
size, the minimum region size is 25M.
- If a region size is equal to 0, bufhigh value
is limited by the supported virtual memory size on the installation.
Region size can be set up as large as the size of the local page data
sets.
- REGION updates
The REGION specifies the total
size of usable virtual storage below-the-bar of an address space.
- MEMLIMIT updates
The MEMLIMIT specifies the total
size of usable virtual storage above-the-bar of an address space.
It can come from the following:
- IEFUSI system exit
- SMFPRMxx MEMLIMT parameter
- SETSMF command
- MEMLIMIT keyword in the JOB and EXEC JCL (that is, z/OS NFS Server
startup procedure). It is worthwhile to update the sample startup
procedure GFSAPROC with an example of a non-zero REGION size and MEMLIMIT.
The System Programmer should also consider if the other jobs
on the installation use virtual memory.