ACF2 for ZVM Backup time not automatically changed at Daylight Savings Time.

Products

• ACF2 for zVM

Issue/Introduction

Whenever DST happens the ACF2 backups happen an hour differently than they are scheduled. 
E.g. time jumped ahead an hour. The backup was running at 1:30 am instead of 12:30 am. 

Environment

Component : ACF2 for z/VM

Resolution

When STP is active, the SYSTEM CONFIG TIMEZONE_DEFINITION and TIMEZONE_BOUNDARY statements are overridden by STP. 
The STP setting is enabled within the FEATUREs section of the SYSTEM CONFIG file. 
It is enabled via the ENABLE STP_TIMEZONE option within the FEATUREs section.

When STP is active, there is no way to interrupt the continuously running ACF2VM Service Machine other than shutting it down or recycling via the ACFSERVE RESTART command. 
A VM System IPL would reset the time zone as well.

With STP disabled, the TIMEZONE_DEFINITION and TIMEZONE_BOUNDARY would be used to set the time zone. 
When the VM System is IPL'd and STP is disabled, the TIMEZONE_DEFINITION and TIMEZONE_BOUNDARY options would be used to set the time zone. 
If the site did not want to IPL and STP is disabled, the site could set the time zone via the SET TIMEZONE xxx command (xxx would be EST or EDT...etc). This command would reset the time zone on the ACF2VM Service Machine via an external interrupt.

The SET TIMEZONE command is invalid with STP active.