s2member process causing memory/server errors

We are migrating a website from a GoDaddy host server to Lunar Pages. This particular site has roughly 12,500 subscribers in s2member. The s2member generally works fine on the GoDaddy server, though there are other server issues. However, when we activate the s2member plugin on the LunarPages installation, the site slows to a crawl and eventually to a standstill. We are getting this record in the server error log:
(12)Cannot allocate memory: couldn’t create child process: /opt/suphp/sbin/suphp for /home/minds30/public_html/wp-content/plugins/s2member/s2member-o.php, referer: http://sphynx.lunarservers.com/~minds30/

We’re in the process of comparing the php.ini files to see what might be different about the settings that could be causing this, but that involves a lot of guesswork. Lunar is running php 5.3.16 and the memory limit is set to 128M. Can you tell us what php settings are crucial to running s2member with that many users, or help us troubleshoot what might be the problem?

Thank you for reporting this important issue.

the s2member-o.php file creates s2Member’s frontend JavaScript and CSS code. You can disable this using the information provided here:

Pre Sale FAQs » How can I prevent s2Member® Pro from loading it’s default CSS?

That should stop this error from occuring in the short term. I’m unsure what’s causing your issue exactly. It doesn’t sound to me like this is a problem with your database’s power. Are your permissions for the s2member-o.php file set to 775?

OK…we have made those changes; is the error message below, which is now being generated every few minutes, of concern?

[Wed May 29 06:33:21 2013] [error] [client 108.56.228.151] SoftException in Application.cpp:256: File “/home/minds30/public_html/wp-content/plugins/s2member/s2member-o.php” is writeable by group, referer: http://sphynx.lunarservers.com/~minds30/

However, when we activate the s2member plugin on the LunarPages installation, the site slows to a crawl and eventually to a standstill. We are getting this record in the server error log:
(12)Cannot allocate memory: couldn’t create child process: /opt/suphp/sbin/suphp for /home/minds30/public_html/wp-content/plugins/s2member/s2member-o.php, referer: http://sphynx.lunarservers.com/~minds30/

Have you asked your webhost about it for more info on what the problem is and what they suggest to fix it? You can mention this is not something you had trouble with before migrating, so they know it’s most likely something with the server configuration and not the site itself.

Could you try this to see if you get any warnings? Knowledge Base » s2Member® Server Scanner

We have talked to the new host, and the problem is the size of the process(es) around s2member. We even had them bump the memory limit from 64 to 128 on the off chance that would help. Running the server scanner was the first thing I did and all reports came back OK.

As it turns out s2member is also noncommunicative with Constant Contact — in fact it shuts down our plugin connecting to CC — so given the number of problems we’ve just switched to WPMUdev.org’s Membership plugin. Thanks for your time.