What is Leap Second ?
Nowadays do you even remember that Earth’s rotation
around it’s own axis determines the length of a day or 24 hours (close enough) ?!?!
The thing is, Earth’s rotation is slowing down,
very slowly, that means the leght of a day is not a precise 24 hours. Since we use Atomic clocks to synchronize
time around electronic devices and those Atomic clocks are damn accurates, from time to time there's a
difference between them. When this difference approaches 0.9 seconds a +1 second is added to
UTC, last time it occurred was on June 30, 2012.
So on Jun 30, 2015 23:59:60 UTC a leap second
will be added.
Pay attention: It will be added at UTC time
zone, if you are on a different zone, the change will occurs at another time of
the day, example: on EST it will occur at 19:59:60.
Now that you understand what Leap Second is,
let’s see how it does impact VMware’s products.
First and most important, it will only,
potentially, affect systems that are configured to receive time synchronization
from NTP server, so I assume everything is affected.
If you are not using NTP for synchronization,
start remediating it NOW.
Second, it depends of how the operational system
handles the Leap Second adjustment and each one will handle that differently.
There’s a common sense that you should change
your NTP to slew mode, which will not make huge adjustments on it’s own time
and will compensate the Leap Second progressively.
VMware’s has created a KB2115818 with all
affected systems and how you address it on every one of them.
Also there’s a KB2121624 which shows systems not
affected by the Adjustment.
Here's a link If you are interested on learn more on Leap Second.
And if you are wondering if it still make sense
measuring our time based on Earth’s rotations here’s another one.
