As the year 2016 ends and 2017 spawns its the correct time for this post, for the Exadata Cell and DB Servers affected with this bug.

We all know or should know that the Second Leap will occur at 23:59:60 on December 31, 2016 UTC and many servers and applications can have some impact with this, but in this article I'll specifically talk about Leap Second for Exadata Database Machine.

For those who work with Exadata and are with Exadata storage and database servers in version 12.1.2.1.0 with the default package ntp-4.2.6p5-1.el6 will have a job before the turn of the year 2017, otherwise cellsrv processes on all Exadata storage servers and Database Servers may restart simultaneously when a leap Second time adjustment occurs.

What is a "leap second"?

A "leap second" is a world wide time adjustment by inserting or deleting one whole second to keep UTC (Universal Time, Coordinated) close to the mean solar time.

List of leap second time adjustments:

at 23:59:60 on December 31, 2016 UTC

at 23:59:60 on June 30, 2015 UTC

SYMPTOMS:

Without the updated ntp package cellsrv processes on all storage servers may restart simultaneously when leap second time adjustment happens (e.g. on December 31, 2016). When this issue is encountered the following messages occur in the cell alert.log:

Cellsrv will have to be restarted, since backward drift in time was more than 300 milliseconds.

ORA-600: internal error code, arguments: [ossmisc:ossmisc_timer_ticks] 

Version affected by BUG Leap Second: Exadata Software Version 12.1.2.1.0 with the default package ntp-4.2.6p5-1.el6

No other Exadata versions are affected.

How to check the version of my Exadata software version? Below I show an example of how to check the version of Exadata Software. (Note: This version below is not affected by Bug Leap Second)

[root@hostname]# imageinfo -ver

12.1.2.3.2.160721


SOLUTION:

Recommended Action - Upgrade to 12.1.2.1.1 (or higher)

The recommended action is to upgrade to Exadata Storage Server software version 12.1.2.1.1 (or higher).

OR

Alternative Action - Update NTP Packages on Exadata Storage and Database Servers

Alternatively, install updated package ntp-4.2.6p5-2.0.1.el6_6 on Exadata storage and database servers.

Perform the following steps to update NTP:

Step 1 - Enable ntpdate Service

Step 2 - Verify Installed Exadata and NTP Package Version

Step 3 - Verify Current NTP Time Offset

Step 4 - Obtain and Stage Updated NTP Packages

Step 5 - Install New NTP Packages

Step 6 - Verify Installed NTP Version


More details Doc ID 1986986.1


Reference Note: Leap Second Time Adjustment and Its Impact on Exadata Database Machine (Doc ID 1986986.1)

Happy New Year and a great 2017 to all.