Server Time Protocol enabled
The enablement of STP is supported. Also, during PR/SM initialization, when STP is enabled, the CPC TOD clocks for each CP are set to the TOD value from STP.
The operating system in each LP can independently choose whether to synchronize to the current time source for STP, if present. Operating systems in LPs that do synchronize to STP run with identical TOD values. Operating systems in LPs that do not synchronize to STP do not need to be aware of the presence of STP and can set their TOD values independently of all other LPs.
z/OS® does not allow you to change the value of the TOD setting when synchronized to STP (STPMODE=YES in the CLOCKxx parmlib member).
- Different local time zone support in multiple sysplexes using the STP Coordinated Timing Network (CTN). Many sysplexes have the requirement to run with a LOCAL=UTC setting in a sysplex (STPMODE=YES) where the time returned from a store clock (STCK) instruction yields local time. To fulfill this requirement, the time initialized for the STP CTN must be local time. With logical partition time offset support, multiple sysplexes can each have their own local time reported to them from a STCK instruction if wanted. For instance, the STP CTN can be set to GMT, one set of sysplex partitions could specify a logical partition time offset of minus 5 hours, and a second set of sysplex partitions could specify a logical partition time offset of minus 6 hours.
External coupling links are also valid to pass time synchronization signals for Server Time Protocol (STP). Therefore the same coupling links can be used to exchange timekeeping information and Coupling Facility messages in a Parallel Sysplex®.