Using the SDSF server

The SDSF server is an address space that SDSF uses to:

Process ISFPARMS statements.
Provide sysplex support. This consists of sysplex-wide data for JES2 devices and for system resources (APF, AS, CK, CSR, DEV, DYNX, FS, ENC, GT, LNK, LPA, NA, PAG, PARM, PS, RM, SMSG, SMSV, SSI, SYM, SYS, VMAP). For more information, refer to Using the server for sysplex data.
Manage the starting and stopping of the SDSFAUX address space. SDSFAUX is used to provide data gathering support and other services for SDSF panels.

It is recommended that you place the SDSF and SDSFAUX address spaces in the medium priority started task WLM service class. For example, STCMD.

As of z/OS V2R4, SDSF includes a server startup option, NOPARM, that allows the server and SDSFAUX to be started, but ISFPRMxx is not processed. When the client then accesses SDSF, a noparm condition is returned by the server and the server falls back to ISFPARMS. The user must have READ access to the SERVER.NOPARM resource in the SDSF class to use ISFPARMS instead of ISFPRMxx.

Note: The NOPARM startup option allows the server and SDSFAUX to be started, and the panels that require SDSFAUX are available. This differs from the NOPARM condition described in Fallback when address spaces are inactive, which requires that the SDSF address spaces are inactive and the panels that require SDSFAUX are therefore not available.

Only a single SDSF (and associated SDSFAUX) address space can be active at the same time. All SDSF users will connect to the one (and only) SDSF address space that is active. An attempt to start a second SDSF address space (regardless of server name) is rejected with a "server already active" message.

You control the server through the MVS operator START, STOP, and MODIFY commands. For details on the commands, see Server operator commands.

Sample JCL for the server is in member ISFSRJCL (alias SDSF) of data set ISF.SISFJCL.

Sample JCL for SDSFAUX is in member HSFSRJCL (alias SDSFAUX) of data set ISF.SISFJCL.

Note: The SDSF server and SDSFAUX address spaces use services to load modules that require SISFLOAD to be present in the system lnklst. If SISFLOAD is not in the lnklst, SISFLOAD must be added as a //STEPLIB in the SDSF server and SDSFAUX JCL procedures and APF authorized.

When SISFLOAD is in the lnklst and LNKAUTH=APFTAB, then SISFLOAD must be added to the APF list.

Fallback when address spaces are inactive

SDSF tolerates the SDSF address spaces being inactive when the user accesses SDSF. If the connect fails during initialization, SDSF continues as a NOPARM condition, as described in NOPARM fallback. When the existing NOPARM condition is recognized, SDSF falls back to ISFPARMS because ISFPRMxx is not available. This fallback requires that the user have read access to the SERVER.NOPARM resource in the SDSF class. If the server is subsequently started while the user is in SDSF, the client attempts to connect when a display requiring SDSFAUX is accessed. However, the user will still be using the fallback ISFPARMS rather than the ISFPRMxx activated by the server.