BUG? File descriptor use in cmd_append (for MULTIAPPEND) results in many open files

Rich Graves rgraves at carleton.edu
Mon Dec 11 13:02:00 EST 2006

Nik Conwell wrote:
> multiple messages being appended).  Cyrus-imapd handles this multiappend 
> by creating stage files for each appended message and leaving the file 
> descriptor open.  The problem is that after 240 messages, we run out of 
> file descriptors and so an open() of the next stage file fails with 
> EMFILE.  I updated /etc/cyrus.conf to make the max fds be 1024 (AFAICT 
> kernel MAX) which helped somewhat but not for larger mailboxes with > 
> 1008 messages.

Excellent troubleshooting. I'm getting worried that I have a problem and 
don't know it. Did you get useful error messages (that we can search 
for, too)?

The man page for cyrus.conf suggests that the default is 256, but that 
the integer value is optional. So if maxfds does not appear in 
cyrus.conf at all, is the default 256, or is it unlimited (up to 
ulimit)? Looks like the former to me. Ick.

> Shouldn't the multiappend/append be closing the FD for each stage file 
> and then reopening it later as it needs it?

Rich Graves <rgraves at carleton.edu>
Sr UNIX and Security Administrator
Ofc 507-646-7079 Cell 952-292-6529

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