Sporadic(?) internal server errors

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yellowled
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Sporadic(?) internal server errors

Post by yellowled » Wed Apr 09, 2014 10:56 am

Just moved two s9y 1.7.8 blog to a new server/hoster for a client. While one works smoothly, the other frequently throws “An internal server error occured.”, then sometimes “The service is not available.” – and then it just works.

I know internal server errors can be tricky to track, so we've already requested an error.log for said webspace (doesn't come with an error.log by default). But since they're running on (literally) the same web host, they have the exact same .htaccess (the standard one generated by s9y), they use the same theme etc., I'm thinking it might be one of the (event) plugins used.

Is that even something worth investigating or do you guys have other ideas/hints where to start debugging this?

YL
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Re: Sporadic(?) internal server errors

Post by garvinhicking » Wed Apr 09, 2014 12:09 pm

Hi!

Yeah, hard to tell. It could be a RAM/Ressourcelimit issue... definitely check the actual error log, only that can help.

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Garvin
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Re: Sporadic(?) internal server errors

Post by yellowled » Wed Apr 09, 2014 12:45 pm

garvinhicking wrote:Yeah, hard to tell. It could be a RAM/Ressourcelimit issue...[/quote|
Which would point to plugins, right? Because both blogs are on the exact same server.
garvinhicking wrote:definitely check the actual error log, only that can help.
Ho-hum. This is funny.

Code: Select all

[Wed Apr 09 12:39:10 2014] [error] [client ::xxxx:xx.x.xxx.xxx] File does not exist: /var/www/virtual/USER/html/favicon.ico
:shock:

Could that actually be it? (I have now uploaded an empty favicon.ico to at least get rid of that error message.)

YL
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Re: Sporadic(?) internal server errors

Post by yellowled » Wed Apr 09, 2014 2:03 pm

yellowled wrote:Could that actually be it?
Probably not. Just now, the blog in question was having the same “Internal server error” issues, but – this is where it gets really funny – the hoster's error.log doesn't show anything. :cry:

Edit: Seems like the log files in the userspace are not updated in real time, so I might still get a proper error message for that occurrence.

YL
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Re: Sporadic(?) internal server errors

Post by Don Chambers » Wed Apr 09, 2014 3:44 pm

I've run into frustrating issues like that... I have found increasing allotted RAM and/or disc space can help. The other day I ran into something where the solution was to rebuild my database tables, though I think I had some sort of error that guided me to that solution.

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Re: Sporadic(?) internal server errors

Post by yellowled » Wed Apr 09, 2014 4:50 pm

Don Chambers wrote:I've run into frustrating issues like that... I have found increasing allotted RAM and/or disc space can help. The other day I ran into something where the solution was to rebuild my database tables, though I think I had some sort of error that guided me to that solution.
I appreciate the input. :)

Again, this is two blogs with the exact same s9y version running on the exact same server of the same hosting company. There should be no difference in available ressources, yet one is running smoothly and the other one throws internal server errors. That's got to have something to do with their individual configuration and/or plugins used, right?

BTW, no entries in the errror.log for the problematic blog for 4 hours now. I think it's safe to assume that the server doesn't throw an error to the log here. Is there a possibility that this “Internal server error” is not actually a server error but an error message thrown by s9y with the same text or something?

YL
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Re: Sporadic(?) internal server errors

Post by Don Chambers » Wed Apr 09, 2014 5:17 pm

Did you run a phoinfo() to see if both are configured the same? Maybe there is a minor difference. And perhaps it is a physical disk and/or memory problem that is affecting one and not the other.

I doubt s9y would be emitting an error message with the same text as a server error.

If you are paying a hosting company for hosting - they should be helping you troubleshoot! :mrgreen:

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Re: Sporadic(?) internal server errors

Post by Timbalu » Wed Apr 09, 2014 7:35 pm

Into the blue some wild guesses: A missing favicon would never stop a system. For me that more sounds as if the bad one uses (identic) ressources (maybe cashed plugin hashes) of the good one and gets pushed in some sort of waiting queue, since the first has priority. Maybe there is a Server-Cache running on that server, which does not properly encapsulates the two different blogs in some areas. Perhaps they even run a SQL Balancer or something.
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Re: Sporadic(?) internal server errors

Post by yellowled » Wed Apr 09, 2014 8:27 pm

Timbalu wrote:For me that more sounds as if the bad one uses (identic) ressources (maybe cashed plugin hashes) of the good one and gets pushed in some sort of waiting queue, since the first has priority. Maybe there is a Server-Cache running on that server, which does not properly encapsulates the two different blogs in some areas. Perhaps they even run a SQL Balancer or something.
Hosting is Uberspace. I know for sure that it is possible to run 2 s9y blogs on the same Uberspace without any issues. I'm also pretty sure they don't run any weird server caches.

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Re: Sporadic(?) internal server errors

Post by lfrantzen » Thu Apr 10, 2014 9:55 am

Hi,

am not 100% sure, but it seems like I have solved the issue. The problematic part seemed to be a piece of script I added to the sidebar via the HTML Nugget plugin. The script comes from Google to embed the Google +1 button you can click to like the site:

Code: Select all

<!-- Place this tag where you want the +1 button to render. -->
<div class="g-plusone" data-annotation="inline" data-width="300" data-href="http://www.blablabla.com/"></div>

<!-- Place this tag after the last +1 button tag. -->
<script type="text/javascript">
  (function() {
    var po = document.createElement('script'); po.type = 'text/javascript'; po.async = true;
    po.src = 'https://apis.google.com/js/plusone.js';
    var s = document.getElementsByTagName('script')[0]; s.parentNode.insertBefore(po, s);
  })();
</script>
I removed that part and now I do not observe any site loading problems anymore, neither at Uberspace, nor at 1&1 (where the same problem existed).

I have to observe this a bit more, but looks good so far!

EDIT:
Problem still exists on 1&1, but not on Uberspace.


Cheers,
Lars
Last edited by lfrantzen on Thu Apr 10, 2014 11:28 am, edited 1 time in total.

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Re: Sporadic(?) internal server errors

Post by garvinhicking » Thu Apr 10, 2014 10:27 am

Hi!

About the log: error.log must not neccessarily contain the fatal PHP errors. Those errors can possibly, if executed as CGI, end up on the central SysLog of the server, on a console screen or even in the global Apache error log. Depending on configuration, the error.log you quote only contains Apache-centric errors, and no PHP problems.

You might want to try to fiddle with php.ini settings, if available, and enable the options

error_log = /path/to/a/writable/php-error.log
log_errors= On

HTH,
Garvin
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Re: Sporadic(?) internal server errors

Post by onli » Thu Apr 10, 2014 12:36 pm

lfrantzen wrote:The problematic part seemed to be a piece of script I added to the sidebar via the HTML Nugget plugin. The script comes from Google to embed the Google +1 button you can click to like the site
That is highly unlikely. The script itself should not make any server calls, so it can't cause this.

This would mean that the error would be generated when s9y parses that code to generate the html-nugget.

Screams of memory exhaustion, if the error is really gone now. Probably would then be caused again (if its not caused by smarty parsing the script-tags, or one of the markup-plugins) by inserting ~the same amount of characters into the nugget.

PS: In fact, I have in the back of my mind the info that function() won't work for smarty in s9y (is that part of the nugget parsed by smarty?). This could cause an error, which could increase memory consumption. Still unlikely though.

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Re: Sporadic(?) internal server errors

Post by yellowled » Thu Apr 10, 2014 12:43 pm

garvinhicking wrote:error_log = /path/to/a/writable/php-error.log
log_errors= On
That's something Lars would have to do himself, I don't have ssh access. See here for how to use your own php.ini on Uberspace.

I'm still pretty sure this is related to one or some of the many plugins used. We'll see if the G+ code was already it.

YL
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Re: Sporadic(?) internal server errors

Post by lfrantzen » Thu Apr 10, 2014 4:10 pm

Hi,

I have another suspect: the flickr Photostream plugin.

Enabling that again led immediately to the error ("An internal server error occurred. Please try again later."). It was disabled together with the G+ code, so I might have been simply wrong by suspecting the G+ code.

What I did now was re-enabling the G+ code and removing the flickr plugin again. For now everything works perfectly, let's see if it stays.

Cheers,
Lars

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Re: Sporadic(?) internal server errors

Post by yellowled » Thu Apr 10, 2014 5:28 pm

lfrantzen wrote:What I did now was re-enabling the G+ code and removing the flickr plugin again. For now everything works perfectly, let's see if it stays.
Something you might also want to think about: reducing the number of posts per page. This is a blog which includes a lot of photos and videos, at least some of them embedded from external services. This will always affect the page rendering performance, so reducing the number of media included from 3rd-party servers will most likely help.

YL
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