Set the z/OS UNIX limits in BPXPRMxx

Remote Systems Explorer (RSE), which provides core services such as connecting the client to the host system, is a z/OS® UNIX based process. Therefore, it is important to set correct values for the z/OS UNIX system limits in BPXPRMxx, based on the number of concurrently active z/OS Explorer users and their average workload. Define OMVS=xx in the IEASYSxx parmlib member to specify which BPXPRMxx parmlib member should be used during IPL.

See "Tuning considerations" in the Host Configuration Reference Guide (SC27-8438) for more information about different BPXPRMxx defined limits and their impact on z/OS Explorer.

MAXASSIZE specifies the maximum address space (process) region size. Set MAXASSIZE in SYS1.PARMLIB(BPXPRMxx) to 2G. This is the maximum value allowed. This is a system-wide limit, and thus active for all z/OS UNIX address spaces. If this is not what you want, you can set the limit only for z/OS Explorer in your security software, as described in Define the z/OS Explorer started tasks.

MAXTHREADS specifies the maximum number of active threads for a single process. Set MAXTHREADS in SYS1.PARMLIB(BPXPRMxx) to 1500 or higher. This is a system-wide limit, and thus active for all z/OS UNIX address spaces. If this is not what you want, you can set the limit only for z/OS Explorer in your security software, as described in Define the z/OS Explorer started tasks.

MAXTHREADTASKS specifies the maximum number of active MVS™ tasks for a single process. Set MAXTHREADTASKS in SYS1.PARMLIB(BPXPRMxx) to 1500 or higher. This is a system-wide limit, and thus active for all z/OS UNIX address spaces. If this is not what you want, you can set the limit only for z/OS Explorer in your security software, as described in Define the z/OS Explorer started tasks.

MAXPROCUSER specifies the maximum number of processes that a single z/OS UNIX user ID can have concurrently active. Set MAXPROCUSER in SYS1.PARMLIB(BPXPRMxx) to 50 or higher. This setting is intended to be a system-wide limit, because it should be active for each client that uses z/OS Explorer.

These values can be checked and set dynamically (until the next IPL) with the following console commands:
  • DISPLAY OMVS,O
  • SETOMVS MAXASSIZE=2G
  • SETOMVS MAXTHREADS=1500
  • SETOMVS MAXTHREADTASKS=1500
  • SETOMVS MAXPROCUSER=50
Note:
  • For more information about other locations where address space sizes can be set or limited, see "Address space size" in the Host Configuration Reference Guide (SC27-8438).
  • The MAXPROCUSER value suggested here is based upon users having a unique z/OS UNIX user ID (UID). Increase this value if your users share the same UID.
  • Ensure that other BPXPRMxx values, such as those for MAXPROCSYS and MAXUIDS, are sufficient to handle the expected amount of concurrently active z/OS Explorer users. See "Tuning considerations" in the Host Configuration Reference Guide (SC27-8438) for more details.
  • During the SMP/E install of z/OS Explorer, you were advised to place the code in a separate file system (zFS of HFS) and update BPXPRMxx to mount this file system during system IPL. Included is a repeat of the sample mount command in case this update still must be done:
    MOUNT FILESYSTEM('#dsn')
   MOUNTPOINT('–PathPrefix–usr/lpp/ibm/zexpl')
   MODE(RDWR)                 /* can be MODE(READ) */
   TYPE(ZFS) PARM('AGGRGROW') /* zFS, with extents */
/* TYPE(HFS) */               /* HFS, auto. extent */