WordPress Generating Site 503s

Discussion in 'General troubleshooting' started by epastuer, Jan 9, 2013.

  1. My question is simple, is this you? Please let me know if you have a solution or if you're encountering the same thing now.

    The problem appears that as soon as we add WordPress to our customer sites that 503 errors generate randomly on the site causing both the child application where the WordPress web app is located and the entire web application to be unavailable for a couple of minutes while the app pool recycles.
    I've laboriously removed our own code as the culprit of the unfortunate event.
    Support says that this is because of too many concurrent HTTP connections (a pretty good accomplishment since these are measured in milliseconds) and I know that WordPress can be a memory hog (although the memory usage monitors I've viewed in the admin page indicate a fairly low memory usage of about 35MB - although I'm somewhat skeptical). It doesn't appear to make a difference on how many restrictions I attempt to apply via the web.config and wp-config to manage the memory and connection limits of the blog, the 503 still comes all the same. While support has even doubled the allotted number of concurrent http connections for me I still seem unable to fix this.

    Is there anyone else out there who has experienced this? If so was there a way in which you were able to resolve this?
  2. ComputerMan

    ComputerMan Winhost Staff

    You wont be able to view how much memory your site is using. You can view the web disk space in the Usage Meter. The memory support is talking about is the amount of RAM memory your site is using.

    For example if you're on the Basic plan your application pool has 100 MB of RAM memory.

    On the Max plan the application pool is allocated 200 MB of RAM memory.

    On the Ultimate plan the application pool is allocated 300 MB of RAM memory.

    The 503 errors are not caused by the application pool recycling but it can be a precursor. For example if your application is coded in a way that will cause the application pool to crash or hang during a recycling and the bad code didn't let it recycle correctly. Then you will get the 503 error message.

    The other thing would be the concurrent connection limit placed on the account. If the concurrent connection limit is reached then the site will display the 503 error message too.

    By default when you first open the hosting account you site is allocated 25 concurrent connection limit. This doesn't mean that only 25 users can visit your site. It means that only 25 HTTP calls can be made at the same exact time. Something like AJAX will take up your concurrent connection limit very fast. But that's just one example.

    From your message you said you already contacted support. Did they give any more information on why you are getting the 503 error messages?
  3. Yup, Yup, Yup

    Hi ComputerMan,

    I have watched this occur on all three hosting plans and it only seems to occur when we introduce WordPress into the equation.

    I very much understand the difference between RAM and memory. There are a couple of (potentially reliable) "RAM monitors" available in WordPress and not to mention that WordPress itself has configurations available to "limit memory usage". While the size of the application pool varies according to hosting plan it seems that the maximum RAM allotment understood in the PHP environment is 128 MB (at least on the 200 MB plan). I have WordPress set at 96 MB and the gauges that I have installed have rarely exceeded 39 MB - skeptical? So am I.

    I also have a rule in the web.config to set the maximum number of concurrent HTTP connections to 48 (not that I can be sure that this affects the php environment) and support bumped up our allotted amount to 50 concurrent connections.

    I do understand that this is the maximum number of HTTP calls that can be made at once on the order of milliseconds so the most probable way for this to occur is via poor scripting or hack attempts and it would be quite the fluke if it were to occur due to 25 (or 50 in my case) simultaneous visits from visitors.

    While bumping up our max connection limit did seem to help, the problem still occurs.

    The first time I contacted support it was due to too many HTTP connections, and after contacting support again it is said that our application is being terminated due to high CPU usage. It doesn't matter which way I seem to go with WordPress, but it appears that I hit some hosting limit that causes the 503 even though WordPress usage seems to be very low.

    I understand that this is a shared hosting environment and that we can only be so greedy, but I really would like to know if this is a common problem with WordPress on Winhost, all shared hosting environments, PHP in IIS or if it is something in the WordPress code itself? (this application seems to be a bear to run if it is causing this much grief)

    Are there several people out there that have this problem or is it due to poor implementation on my part?


    Last edited by a moderator: Oct 14, 2015
  4. ComputerMan

    ComputerMan Winhost Staff

    Hi Eric,

    If support said that the cause was from high CPU usage and this happen after you've installed WordPress.

    Then in order to resolve your problem:

    You need to download your whole site. (Not just the wordpress application). Your whole site meaning all of the web applications installed on the single hosting account.

    Put the site on a single application pool. (Just like our hosting environment is set up on our web servers for your site account) Set the following limits on the application pool locally:

    1) More than 20 minutes of idle time (no HTTP request in 20 minutes)
    2) The application uses more than 100 MB of memory for the Basic plan and 200 MB of memory for the Max and 300 MB of memory for the Ultimate plan.
    3) The application uses more than 70% of CPU resources for more than 5 minutes

    Then you will be able to see what is using the high CPU resources and check to see if you can optimize your site. So it doesn't use a lot of CPU resource on our web server.
  5. I too am experiencing Wordpress 503 errors

    Hi Eric

    I too am experiencing the same 503 error on my Wordpress site hosted on a Winhost Max Plan. Support also said that my issue was due to too many concurrent HTTP connections. I have have requested my default concurrent connection limit be increased to see if that helps, but have not gotten a response yet.

    I just thought I would share that I am having the same issue and would hope that someone of the forum has a suggestion for a more permanent fix. Likewise, I would like to know if others are having the same issue before I go shutting down all my plugins, one by one, to see if one of those are a culprit.
    Last edited by a moderator: Oct 14, 2015
  6. ComputerMan

    ComputerMan Winhost Staff

    If its the HTTP concurrent Connections. We should have provided you with the HTTP Error logs showing what pages were requested during the 503 errors and it should point you in the right direction as to what page is causing it.

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