Monday, March 2, 2015

Scheduling FINAL on backup master

FINAL is the job stream that in TWSd extends the plan for the next period.
I've already covered some best practices about FINAL in this article: Scheduling FINAL (Best Practices)
In this article I'll show a common best practice that is used to automatically schedule FINAL on the current active master, in order to assure High Availability. Even if common, and we use it on our SaaS environments, this best practice is not known from all the users and requires some customization.

Built-in mechanism for high availability / disaster recovery in TWSd is based on the backup master, this is an active-passive configuration where the active master role can be move to the backup master using the switchmgr command. This can be done for planned or unplanned outages and remove the single point of failure of the master.
However this is not sufficient for long term unavailability of the original master, by default the FINAL job stream is scheduled to run on the master, and in this condition the schedule FINAL job streams will not run and the plan will not be automatically extended.

The immediate solution is to cancel the FINAL on the old master and submit a new FINAL running on the new master, in addition the workstation definition in the DB must be changed to set the current master as the master also in the DB.

If the master is running on any Unix platform, a more automated solution is available using a unixlocl XA (extended agent):
  • Create a new XA workstation (e.g. MASTER_XA) with "unixlocl" access method and "$MASTER" as host workstation.
  • Change localopts on master and backup masters to set "mm resolve master = no".
  • Change FINAL and FINALPOSTREPORTS jobstreams to move the job streams and all the jobs from the master to the new XA (using composer be careful that just using modify will actually clone your FINAL, use rename instead of modify or delete the old one at the end).