When your server’s time doesn’t match an authoritative time, such as ntp.org, you have a problem called time drift. This problem is incredibly common and happens slowly over weeks and months. To easily check the time drift, compare the server’s current date and time to The Official NIST Time. Make sure you are comparing to the correct time zone.
Possible issues caused by time drift on a cluster of servers include:
Syncing your servers with a common time server ensures that your applications all operate on the same time and avoid these problems. NTP (Network Time Protocol) is a daemon that makes small, innocuous changes to the server’s clock to negate time drift.
We also recommend you use the UTC time zone on everything (though we won’t create a recommendation for this particular suggestion).
Manually change the date and/or time on your servers. Keep time zones in mind.
Use ntpdate to perform a one-time sync on all your servers to the ntp.org pool in your region. Once synced, use the NTP daemon specific to your OS to manage time drift.
If you have many servers that need to be closely in sync, you should manage your own NTP server that syncs to an NTP pool.