blank email (error 500 in horde) with big attachments

[nick at netdome.biz]

Hello Xavier,

> Thanks for the help. I was thinking about a memory problem but didn't know
> where to start.
Right, when I run into the same problem, it was not easy to debug, either.

> What really troubles me is that there is absolutely nothing regarding this
> error in Apache logs (even in debug mode).
I helped myself with a "tac <thatlogfile> | grep 500". That led me into
the right direction. It's not that easy to debug a fully-running system,
logs get clogged easily.

> While I'm experienced with Apache + Perl or cgi,  I have a very limited
> knowledge on Apache + PHP. In the template, I've found this, with Perl I
> would increase each value, should I?
[..]

You're absolutely right. I'm pasting my suggestions:

max_execution_time = 180
max_input_time     = 180
memory_limit       = 256M
post_max_size      = 25M
upload_max_filesize = 25M

I had to put memory_limit to 256M to ensure that handling attachments with
a total size of ~ 25 MB actually works. (I tried 128, 196 MB before that.
192 MB failed with attachments > ~20 MB.)
Max_execution_time/max_input_time is unusually high, but needed for slow
connections to finish their upload. I might try to tweak all those entries
closer to their "really needed values", but am happy enough for the
moment.

bye,
Nick