Due to resource limits on our Shared Hosting machines, it is not possible to allocate more than 20M of memory to PHP, although phpinfo() may report a higher number. You will be unable to increase the memory usage limit with a php.ini file.

O.k., first off why would they allow your to specify a higher number in PHP if they are going to ignore it? According to PHP if a script runs out of memory it will report with a message like this: “Fatal error: Out of memory error.” However, because of 1and1 allow PHP to think it has more memory and then killing it when it exceeds 20M, no error message is reported. I run across this situation on a different project in the past when processing images.

So I decided to test to see if this could be the case. The best page to test I found was the Tools->Import page. That page seem to be the one most likely to stop loading and blank out. It would load all of the admin menus but would not load the import list when some plugins were activated. So I added a few memory_get_usage() function calls and sure enough it appears that whenever the memory when above about 15,300,000 bytes of memory it would die. This is lower than 20MB but memory_get_usage does not necessarily report all memory used as seen by the OS.

Therefore, I must conclude that it is a PHP memory issue and that 1and1.com poor decision to allow PHP to report and indeed set a higher memory limit than 20MB but ignoring that number anyways suppresses the error message resulting in very odd behaviors. Since, Wordpress is a good well used piece of software this is a grave shortfall for 1and1 hosting especially at the developer level. I therefore am in search of a new host as I am not going to continue to pay money to a host with such a poor limit and support of PHP.  Hopefully this post might shed some light on odd problems you might be having with Wordpress on 1and1.

Related posts:

1. Wordpress, PHP Memory, and 1and1.com part 2
2. Upgrading Wordpress to 2.7.1