Setting the TOD clock accuracy monitor service

The TOD clock accuracy monitor service allows the specification of an acceptable time deviation for the TOD clock from the current external time source (ETS). This service is disabled unless a non-zero value is specified for the ACCURACY parameter in the active CLOCKxx member of SYS1.PARMLIB. This service is activated only if the CEC is operating in an STP-only Coordinated Timing Network (CTN) using one of the following External Timing Sources (ETS) as the source of time:

The dial-out service on the HMC.
A Network Time Protocol (NTP) server.
A NTP server with a pulse per second output option.

Note: The ACCURACY value specified is with respect to the ETS time, which may deviate from Universal Coordinated Time (UTC) by a small amount. See section 2.3 of Server Time Protocol Planning Guide Redbook, SG24-7280, for additional details of the ETS accuracies.

If the ACCURACY value is non-zero and the system requirements are met, message IEA034I 'THE TOD CLOCK ACCURACY MONITOR IS ACTIVE' is issued.

If the ACCURACY value is non-zero, but the system requirements are not met, message IEA036I 'THE TOD CLOCK ACCURACY MONITOR IS NOT ACTIVE' is issued at IPL.

If the TOD clock exceeds +/- the ACCURACY value, message IEA032E 'TOD CLOCK ACCURACY LIMITS MAY HAVE BEEN EXCEEDED' is issued and then re-issued every one hour until the condition is corrected. Possible corrective actions are:

Allow the system to correct the time difference on its own. Note: This may take up to 7 hours per every second of deviation to correct.
Follow your installation's clock synchronization process. Note: This may cause outages of the partitions on all the affected CEC(s).
Shut down the CTN, deconfigure it, and then use the Set or Adjust the Time panel on the Hardware Management Console (HMC) to correct the time on the CEC. Next, reconfigure the CTN, and then re-IPL the partitions.

If the TOD clock exceeds +/- the ACCURACY value, but drifts back or is corrected to be within the specified tolerance range, message IEA033I 'THE TOD CLOCK IS NOW WITHIN SPECIFIED ACCURACY BOUNDS' is issued.