This article provides information on Odin virtualization family products and leap seconds.
A leap second is a one-second adjustment that is occasionally applied to Coordinated Universal Time (UTC) in order to keep its time of day close to the mean solar time
The International Earth Rotation and Reference Systems (IERS) recently announced that an extra second will be injected into civil time at the end of June 30th, 2015. This means that the last minute of June 30th, 2015 will have 61 seconds. If a clock is synchronized to the standard civil time, it should show an extra second 23:59:60 on that day between 23:59:59 and 00:00:00.
Clocks in IT systems do not always follow the standard above and can behave in many different ways:
- Red Hat systems repeat 59th second instead of injecting 60th second. Since linux-based Odin virtualization products are based on Red Hat kernel this behavior is also true for the servers running on
vzkernel. (check corresponding Red Hat article for more information).
- Windows time servers ignore the leap second signal and will sync to the correct time after the leap second (see How the Windows Time Service Treats a Leap Second for more information).
- If a clock doesn’t connect to a time synchronization system, it drifts on its own and will not implement any leap second or an adjustment for it.
To sum up:
- For servers which do not synchronize time with NTP server, and for Windows machines - you will not even notice the leap second.
- For Linux servers synchronized with NTP server - you will receive 59th second twice. It should not affect any services significantly and no issues are expected. Regardless, just to make sure system will be stable, it is recommended to install latest kernel update.
Note!: Make sure all servers participating in pstorage are using same time synchronization settings. Time should be in sync between nodes in cluster.
Following resources might be helpful: