mmap failed messages in syslog

[Shawn Heisey]

On 5/9/2018 10:15 PM, Shawn Heisey wrote:
> It's been about three weeks since I asked this question.  All the 
> information I have available says that all users have no limits on 
> virtual memory, so it must be dovecot itself that sets the limit.  Can 
> that be changed in the 1.2 version?  I can't upgrade to 2.x yet.
>
> Here's an actual syslog entry, redacted to remove identifying info:
>
> May 9 21:55:48 frodo dovecot: IMAP(REDACTED1): mmap() failed with 
> index cache file /home/vmail/REDACTED2/dovecot.index.cache: Cannot 
> allocate memory
>
> The file that it could not mmap here is 189843456 bytes.

I may have figured it out.  After a little googling to see how virtual 
memory limits are set in C programs, and then some grepping of the 
1.2.15 dovecot source, I saw evidence that setting the mail_process_size 
value in dovecot.conf can increase the limit on virtual memory.  I have 
done this, and will keep an eye on the log to see if it helps.

Thanks,
Shawn