Clarify new CPU limits

[iseletsk]

Send it to me direct. i@cloudlinux.com
yeBTW:
when they crashed it -- was it apache process that became really big/ate up all the RAM? If yes, are you using mod_security with output filtering?

[denis]

Hey Igor, yes it was the Apache process that ate all the ram and swap. I am using Atomics (paid) rulesets for cpanel which i *think* do include output filtering

[iseletsk]

The issue is related to a bug in mod_security output filter. The way it works -- it collects all the output (from script), and then checks it against a number of regexps to see if output doesnt leak any sensitive info, like credit card numbers.
It is all good, until you try to output infinite amount of info (as in case of infinite loop that outputs something on each iteration). To store all that output, you would need infinite amount of RAM, and that is why your httpd processes balloon in size.
We had somewhere a script that kills big httpd processes, but this is still bad for performance (as big httpd process evicts caches). Right solution would be to disable (or fix) mod_security output filters.