MAXFILEPROC
Use MAXFILEPROC to set the maximum number of file descriptors that a single process can have open concurrently, such as all open files, directories, sockets, and pipes. By limiting the number of open files that a process can have, you limit the amount of system resources a single process can use at one time.
You can use the USS_MAXSOCKETS_MAXFILEPROC check provided by IBM® Health Checker for z/OS® to determine whether the MAXFILEPROC value is set too low. For more details about IBM Health Checker for z/OS, see IBM Health Checker for z/OS User's Guide.
- For conformance to standards, set MAXFILEPROC to at least 16 to
conform to the POSIX standard or at least 25 to conform to the FIPS
standard.
Guideline: Set this value to 64000.
- The minimum value of 3 supports stdin, stdout, and stderr.
- The value must be larger than 3 to support shell users. If the value is too small, the shell might issue the message “File descriptor not available.” If this message occurs, increase the MAXFILEPROC value.
A process can change the MAXFILEPROC value using the setrlimit() function. Only users with appropriate privileges can increase their limits.
ALTUSER userid OMVS(FILEPROCMAX(nnnn))
Dynamically changing certain BPXPRMxx parameter values explains how to dynamically change the MAXFILEPROC value.