Hitting Host's 500 MB Memory Usage (RAM) Limit

Hi Everyone,

My hosting provider is in the process of upgrading to CloudLinux, which enables them to impose memory usage (RAM) limits on each account on a server. The limit they’ve imposed is a 500MB cap. They’re doing this to keep one site/account from monopolizing resources and slowing down the others and/or causing outages.

I have multiple wordpress sites hosted with them, a few on differing servers (it’s a reseller account), and now all of my sites are running into issues loading because they are hitting the memory usage limits.

In any case, the entries in my site’s error log all look something like this:

[Thu Apr 28 14:50:51 2011] [error] [client 75.xxx.xx.xxx] (12)Cannot allocate memory: couldn’t create child process: /opt/suphp/sbin/suphp for /home/zicl/public_html/wp-content/themes/headway-101/media/css/layout.php, referer: http://www.examplesite.com/wp-content/themes/headway-101/style.css

[Thu Apr 28 15:00:27 2011] [error] [client 75.xxx.xx.xxx] (12)Cannot allocate memory: couldn’t create child process: /opt/suphp/sbin/suphp for /home/imq/public_html/wp-content/themes/headway-101/media/css/typography.php, referer: http://www.examplesite.com/wp-content/themes/headway-101/style.css

And the WP errors logs have entries like this:

[28-Apr-2011 04:32:37] PHP Fatal error: Out of memory (allocated 20447232) (tried to allocate 131072 bytes) in /home/imq/public_html/wp-includes/functions.php on line 3071

[27-Apr-2011 23:53:05] PHP Fatal error: Out of memory (allocated 18087936) (tried to allocate 78 bytes) in /home/zicl/public_html/wp-includes/formatting.php on line 949

The host is, of course, blaming the issue on WP and my plugins/themes. However, the sites all use themes from popular providers such as Thesis, Headway, Studiopress, and WooThemes. Most sites only have 1-3 plugins, all of which are popular and vetted by many users. No caching plugins, no cron jobs, etc. Nothing resource-heavy. These are cpanel accounts, and most have fewer than 500 visits/day and between 50-1000 pages/posts.

My question is, should 500MB RAM memory usage limit be too low to run WP? Or does every one of my sites have some kind of issue that makes them take up more memory than they should? They were built at different times, on different servers, with different themes, and so I am kinda at a loss here.

If anyone could provide any insight, I would be very, very, very appreciative. I am really stressed right now, as I’ve worked my tail off for years to build a business that supports my family, and right now my income has been cut back to a trickle.