Apache Abnormal Memory Consumption, Causes?

@Stew

I expected to see more specific errors, but it looks okay in general. The reason I wanted to see the list of log files, was because sometimes Apache behaves in a strange way, if the log files grow to a very big size.

One thing I’m noticing, some of the sites are running WooCommerce, which is a very heavy WordPress plugin, so if you are running multiple WordPress sites and some of them using WooCommerce, then you might actually run out of RAM.

But it’s still weird that it didn’t make any difference, when you removed a couple of sites. Let’s see we can get some expert assistance.

@jtittle Have you seen this before? Apache using all memory with multiple WordPress+WooCommerce. You know what my off-the-bat recommendation would be.

Hi @Stew

There can be many reasons why, but I would think this might have something to do with PHP running as a module in Apache. Let’s see if the error logs tells us anything.

Can you run this command and post the list?

ls -lh /var/log/apache/

And then run this and post the output:

tail -50 /var/log/apache/error.log

@Stew @hansen

From looking at error.log output, the client denied by server configuration error is probably due to VirtualHost blocks not having a <Directory ...> block setup to allow the request through.

Apache differs from NGINX in that you have to allow access to directories instead of restrict access.

If you intentionally restricting access to that file, since it seems to be repetitive, then you may have a correct setup and the errors are just logging that access was denied. I’d have to see the VirtualHost blocks to really make that call, as well as your .htaccess file(s) – for each site.

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As for the RAM usage, restarting the server will normally always brings things back online as you’re flushing everything when you do that. Everything starts from square one all over, resource usage begins to creep up, and then you’re back in the same situation.

The issue here, beyond the above errors, seems to be a matter of WordPress + WooCommerce, plus from what I can gather from the log, around 9 websites.

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If each of those 9 sites are WordPress + WooCommerce:

1). 2GB of RAM most likely isn’t enough. WooCommerce is a heavy plugin and normally, in my past dealings with it, needs at least 1GB per instance (WordPress + WooCommerce).

2). Beyond RAM, you need to look in to optimizing your stack. This includes optimizing Apache, PHP, MySQL, etc. Default configurations are only starting points, they are not meant for production, so if you’ve not tweaked/tuned your stack, it’s not going to perform as well as it could/should. If you’re not able to do this yourself, I’d definitely recommend hiring a sysadmin (hey…I’m available :-)).

3). Beyond the first two, the hint that @hansen dropped would be dropping Apache in favor of NGINX as your web server, which I’d honestly recommend as well. It’s more performant and would likely reduce some of the RAM consumption alone, though you’d still need to look in to optimizing your stack for better performance and resource usage.

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You can take the easy route and throw hardware at it (i.e upgrade to 4GB or 8GB), but you’ll soon be back with the same issue as throwing hardware at it only works for so long. Part of running a sever is optimization or hiring a sysadmin to do it for you. Beyond that, maintaining security, server updates, and perhaps most important, since it seems your current version is out of date, keeping WordPress and WooCommerce up to date as well.