Using the SDSF server
- Process ISFPARMS statements.
- Provide sysplex support. This consists of sysplex-wide data for JES2 devices and for system resources.
- Manage the starting and stopping of the SDSFAUX address space. SDSFAUX is used to provide data gathering support and other services for SDSF panels.
The SDSF server is required for SDSF 2.5 and later. 
It is recommended that you place the SDSF and SDSFAUX address spaces in the medium priority started task WLM service class. Because SDSFAUX is responsible for data collection, it should be placed into a higher priority WLM service class. For example, SDSF could be placed into STCMD and SDSFAUX placed in STCHI.
SDSF includes a server startup option, NOPARM, that allows the server and SDSFAUX to be started and the panels that require SDSFAUX are available, 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.
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.