Amavisd cant fork with a lot of emails

[Antonio Gutiérrez Mayoral]

Hi all!

First of all, sorry if this is not the right place to ask this
question. We are setting upan antispam server using spamassassin,
maia, amavisd-new, etc. All is ok. But, once in a while, we have
problems in amavis, when create a new process to check attached data
in an email.

We are getting an strange message on postfix logs after a while. The
message is like that:

(host 127.0.0.1[127.0.0.1] said: 451 4.5.0 Error in processing,
id=11968-01-10, mime_decode-1 FAILED: run_command (open pipe):

Can't fork at /usr/lib/perl5/5.10.0/x86_64-linux-thread-multi/IO/File.pm
line 188. at /usr/sbin/amavisd line 1657. (in reply to end of DATA
command))  YYYYY <at> foo.bar

I am afraid that the problem is there isn't enough resources to
allocate a new thread. The message goes to the deferred queue. The
problem is, that when its occurs, the deferred queue starts to
increase quickly, and the memory goes down quickly also. For this
reason I have configured via limits.conf to increase the process on
the * account, but it doesnt works:

/etc/security/limits.conf

*       soft    nofile  65535
*       hard    nofile  65535
*       soft    nproc   65535
*       hard    nproc   65535

Amavis is running under the amavis user account. My server is a SLES
11 (virtual running under VMWARE), with 4 GB of ram
and 1,5 GB of swap. When I have this problem, the free memory quickly
goes down, like the swap. :(((

Any ideas? So much thanks.

Antonio.


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Antonio Gutiérrez Mayoral <agutierr at gmail.com>