I have just learned that there will be a leap second before January 1, 2017. A leap second is an extra second added to a day to keep UTC (Coordinated Universal Time) synchronized with "mean solar time". The leap second is added to December 31, 2016, after 23:59:59 UTC, and before 00:00:00 UTC on January 1 2017.
|December 31, 2016||23:59:59 UTC|
|January 1, 2017||00:00:00 UTC|
The question is how does this effect IBM i?
IBM made an announcement in July of this year describing its effect on IBM i.
The IBM i Operating System will not be affected by the Leap Second Adjustment. The IBM i Operating System will not automatically add the leap second at the end of December 31, 2016, at 23:59:60 UTC.
If your IBM i Operating System is configured to to utilize the NTP time protocol service via the network, the leap second will be adjusted by this service.
If your IBM i Operating System is not configured to utilize the NTP time protocol service via the network, you will need to make the leap second adjustment manually by changing the QTIME system value.
You can configure NTP on IBM i using the Change SNTP attributes, CHGNTPA, command. This should be performed by a system administrator, and I am not going to give details on how to do this except to provide a link to IBM's documentation for this command at the bottom of this post.
If you do not use NTP then you will need to adjust the time manually after January 1, 2017 00:00:00 UTC. The exact time depends upon which time zone your IBM i is in.
The last leap second was on June 30, 2015.