Clock Skew

Clock Skew

Einstein famously discovered that all time is in fact relative. This is all very well when travelling at near-light speed or when considering theoretical inter-galactic spacemen, but for monitoring SQL Servers, knowing the correct time can be a big issue.

We’re currently having some pretty brow-furrowing, head-scratching discussions about how to handle the synchronization of time between servers when collecting their monitoring data. If the time on one server differs from that of another, by minutes or even seconds, then it could cause some rather obvious weird behaviour in SQL Response – delays in data display, odd-looking axes on graphs, and even alerts for future events.

So, we thought we’d ask you what your experience of this issue is, and how you think we might handle it. Specifically, we’d like to know:

  1. Are your server times all synchronized?
  2. If so, how do you keep them synchronized?
  3. Have you ever experienced any SQL Server issues because of clock discrepancies?
This entry was posted in Metrics and tagged , , , . Bookmark the permalink. Post a comment or leave a trackback: Trackback URL.


  1. Posted January 22, 2010 at 2:57 pm | Permalink

    1. Yes, completely synchronized.
    2. We use a time server
    3. Yup, we’ve run into SSPI problems when the clocks aren’t sync’d up correctly (especially if there is a discrepancy with the DC)

    • Tom
      Posted January 25, 2010 at 3:16 pm | Permalink

      Thanks Nic.

      It’s interesting to hear that you have experienced problems due to clock discrepancies.. it can be a really nasty problem.

      We think we might even add an alert in V2 when we notice clocks are out.

  2. jonathan allen
    Posted January 26, 2010 at 3:29 pm | Permalink

    1 – Yes

    2 – Network server with specified task polls authorised internet time source server place thing. Other servers poll this server across our WAN

    3 – No. See 1 and 2

Post a Comment

Required fields are marked *

Add an Image


You may use these HTML tags and attributes: <a href="" title=""> <abbr title=""> <acronym title=""> <b> <blockquote cite=""> <cite> <code> <del datetime=""> <em> <i> <q cite=""> <strike> <strong>