[Dovecot] failed: Too many open files

[Masaharu Kawada]

Dear list,

I have questions about content of the following error messages.

---</var/log/secure>---
dovecot-auth:　PAM　unable　todlopen(/lib/security/pam_nologin.so)
dovecot-auth:　PAM　[error:/lib/security/pam_nologin.so:　cannot　open　shared　object　file:　Too　many　open　files]
dovecot-auth:　PAM　adding　faulty　module:/lib/security/pam_nologin.so
dovecot-auth:　PAM　_pam_load_conf_file:　unable　to　open　/etc/pam.d/system-auth
dovecot-auth:　PAM　unable　to　dlopen(<*unknown　module　path*>)
dovecot-auth:　PAM　[error:　*unknown　module　path*>:　cannot　open　shared　object　file:　Too　many　open　files]
dovecot-auth:　PAM　adding　faulty　module:　<*unknown　module　path*>
dovecot-auth:　PAM　_pam_load_conf_file:　unable　to　open　/etc/pam.d/system-auth
dovecot-auth:　PAM　_pam_load_conf_file:　unable　to　open　/etc/pam.d/system-auth
dovecot-auth:　PAM　unable　to　dlopen(/lib/security/pam_deny.so)
dovecot-auth:　PAM　[error:/lib/security/pam_deny.so:　cannot　open　shared　object　file:　Too　many　open　files]
dovecot-auth:　PAM　adding　faulty　module:/lib/security/pam_deny.so

---</var/log/maillog>---

dovecot: auth(default): pam(xxx at xxx.com,127.0.0.1): pipe() failed: Too many open files
dovecot: auth(default): pam(xxx at xxx.com,127.0.0.1): pipe() failed: Too many open files

It seems that this is due to that there are files existed to open beyond
its limitation.

Other information that could be relevant are as follows.

# ulimit -n

1024

# cat /proc/`cat /var/run/dovecot/master.pid`/limits
cat: /proc/7273/limits: No such file or directory


# lsof -p `cat /var/run/dovecot/master.pid` | wc -l
29

# ls /proc/`pidof dovecot-auth`/fd | wc -l
1024

>From the above result, dovecot-auth proccess opened 10243
files, and that seems to be the limit. So I expect that
adding following lines into /etc/init.d/dovecot could be
fix this issue.

# vi /etc/init.d/dovecot
---
. /etc/init.d/functions

ulimit -n 4098    <-add
test -x /usr/sbin/dovecot || exit 0   <-add

if [ -f /etc/sysconfig/dovecot ]; then
    . /etc/sysconfig/dovecot
fi
---

Is my understanding right? Even if so, how could I verify
what files are opened by dovecot-auth?

I would very much appreciate it if someone in this list
could provide comments/suggestions.

Sincerely,