In the last week I've been coming across an incredibly annoying error on one of Slicehost slices. It appears that every now and then PHP will fail with a fatal error, saying a certain function is undefined. The function changes, but is always a core PHP function e.g. defined(), version_compare(), etc. This problem has occurred while using several different PHP applications - PHPMyAdmin, my own custom built apps, etc, leading me to believe that the problem is not specific to the running code.

Here are some details: - Debian Lenny - Apache 2.2.9 - PHP 5.2.6-1+lenny4 with Suhosin-Patch (running eAccelerator 0.9.6)

Apache and PHP are installed from Debian packages. Error logs show nothing out of the ordinary.

I thought memory might be an issue, but free -m reports upwards of 100MB free almost all the time. Another thing I'm trying to investigate is if the problem might be related to eAccelerator, but testing this theory out is incredibly hard because the issue doesn't appear very often and I've been using eAccelerator for months on this install without any problems up until now.

Has anyone ever come across anything like this? Why would PHP report undefined core functions?