Agent DST bug

We recently discovered an issue that affects Datadog Agents only on servers with clocks set to Daylight Saving Time (DST). If your servers' clock are set to DST, you should upgrade the Agent to v5.0.5 before DST ends or restart the Agent shortly after DST ends. DST ends on Sunday, November 2nd, 2014 at 2AM local time.

If your servers' clock are set to UTC or to a timezone without DST, you can ignore this message.

Impact of the DST bug

If the server's clock is set to DST (instead of UTC), the Agent will stop sending metrics for up to one hour after DST ends, or until it is is restarted. In the United States for instance, this is happening this Sunday (November 2nd 2014, 2AM local time).

In practice this means that the agent will collect metrics but won't report for up to one hour after DST ends. If the agent is restarted in this hour, it will resume reporting normally.

If you have monitors on metrics with timeframes shorter than 1 hour, you may receive spurious alerts coming from the affected Agents.

What you can do to avoid the DST bug

You have 2 options.

1. Upgrade the Agents on the affected servers to 5.0.5 (Agent install instructions)
2. Schedule an agent restart shortly after DST ends (e.g. use cron to restart the agent at 02:01 local time)

How to tell whether your servers are affected

If you are using Linux/Unix, simply run date on your servers. If they read Fri Oct 31 22:00:56 UTC 2014, your servers is not affected. If they read something like Fri Oct 31 18:09:09 EDT 2014 they are affected.

On Windows, simply look at the time in the task bar.