My site is suffering from huge server CPU load and I don't know why.

kewlratskewlrats New
edited December 2011 in Internet & Media
Hi folks!

I've been running my site, SideQuesting.com, for almost 3 years now. We run Wordpress with a few plugins on a LiquidWeb VPS with 1GB.

We just switched to LiquidWeb because we started having a spike in our server's CPU memory load while we were hosted at HostGator on a shared server. The team at Hostgator suggested that we switch to a VPS to allow for the memory loads, so we switched to LiquidWeb based on the word of a few close friends.

However, the same issue is happening there as well. Our CPU load is astronomical (99% memory with the "swap" hitting high levels as well). Our site had much higher traffic numbers a few months ago and never crashed... and we were on a shared server back then as well.

because this is happening on a VPS and was happening on a shared server before it, I am inclined to think that this might be a Wordpress or database issue. None of our images are being linked to (that I know of) at high traffic.

Is there a specific way to check what the issue is? When I ask the LiquidWeb folks, I am essentially upsold to a 2GB server instead of having my question answered as to what the issue is. I'd love to have someone poke around and take a look at my set-up... whenever my site comes back up.

Frustrated is putting it lightly.

Thanks,
Dali :(

Comments

  • ShortyShorty Manchester, UK Icrontian
    edited December 2011
    Hi Dali,

    How comfortable are you with server configuration? Getting onto the shell, check a few obvious things:

    1. Run a netstat and see how many concurrent connections you have going (you got loads, you got a problem)

    2. Do a TOP output to look for what processe(s) are running hot (guessing httpd here), look at your load averages and how much memory in use/swapping

    Even that at the most basic level should give you some indication.

    Then start delving a little deeper.... (logs, lots and lots of logs!)

    Dan
  • ardichokeardichoke Icrontian
    edited December 2011
    If you have a VPS at LiquidWeb, that means you're paying for support. You should open a support ticket and have a tech look into things for you.

    Additionally, if you aren't already you should definitely be using a caching plugin for WordPress. I personally prefer W3 Total Cache. With proper tweaking it can tame most WordPress sites.

    Finally, the thing no one wants to hear, the possibility exists that you may need to upgrade (look into talking to support and tweaking your site first). The fact of the matter is that a VPS isn't really an upgrade from shared hosting in most cases. Shared hosting means that your site is hosted on dedicated hardware, just with a bunch of other sites. Generally speaking, a shared server is going to have more resources available to handle load spikes than a VPS. If your site was overloading a shared server by itself, a VPS (which has strictly limited resources available to it) is only going to have worse problems.
  • kewlratskewlrats New
    edited December 2011
    Thanks for the input! I'm already using W3 Total Cache. I hope I have it configured right.

    My shared host asked that I upgrade to a VPS because of the spikes, and had even suspended us in the process. I switched to LiquidWeb to get my VPS because they're local.

    This hasn't happened before to our site. We've had a ton of traffic in the past, far greater than now, and handled the load well. So, we're kind of dumbfounded as to why this happens to us, now 2-3 times per day.
  • ardichokeardichoke Icrontian
    edited December 2011
    If they suspended your site on the shared server, they did it because it was destabilizing the entire server. In other words, your site was able to overload a dedicated server. If your site is capable of overloading a dedicated server, it will overload a virtual server. The fact of the matter is, for your situation, a VPS wasn't an upgrade.

    The benefits of a VPS over a shared account are that you have full control over your environment and you don't have to share any of your resources with any other sites. The downside, however, is that a VPS doesn't have as many resources as a server used for shared hosting. If your site can overload a shared box, it will absolutely overload a VPS.

    Once again though: put a support ticket in with LiquidWeb support. They would be the people that can best help you with your problem as they actually have access to look into exactly what's going on.
  • ShortyShorty Manchester, UK Icrontian
    edited December 2011
    Did you actually even look at any of the suggestions I made? You could catch a whole host of useful metrics there.

    Either that or log a ticket. If you are paying for tech support, use it :)
  • HatopHatop Alabama
    edited December 2011
    More detailed information would allow me to offer some help, however from what you've said I'd investigate the following areas:
    1. Possible Denial of Service
    2. Possible scripting issue
    3. Possble SQL issue
    4. Out of date Wordpress module conflicting with a version of PHP


    There are many other reasons but I'd need to see more information on your environment, how the server responds to a mild load, specific versions of all modules and wordpress, specific versions of php mysql and apache(or http server of your choice), etc.
  • Hi Dali,

    How comfortable are you with server configuration? Getting onto the shell, check a few obvious things:

    1. Run a netstat and see how many concurrent connections you have going (you got loads, you got a problem)

    2. Do a TOP output to look for what processe(s) are running hot (guessing httpd here), look at your load averages and how much memory in use/swapping

    Even that at the most basic level should give you some indication.

    Then start delving a little deeper.... (logs, lots and lots of logs!)

    Dan
    Dan, I've been having the tech support at LiquidWeb help me with a few of the questions, and they've been sending me feedback on a regular basis as to what is causing the loads... but it's completely different each time (different PHP scripts, different pages, etc).

    I'm not proficient enough to do either of the things you're asking. Actually, I have no idea how. Is there a link that shows how to do either?

    Thanks!
    Dali
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