limits.conf setting doesn't 'stick'

Question

Trying to get the equivalent of ulimit -n 20000 on a high load web server, however the /etc/security/limits.conf on ubuntu hardy doesn't seem to stick.

here is what I set in the config file.

root             soft    nofile         20000
root             hard    nofile         20000
www-data             soft    nofile         20000
www-data             hard    nofile         20000

I also tried

*             soft    nofile         20000
*             hard    nofile         20000

after rebooting, when i run ulimit -n on root, or www-data or my regular user i still see the default 1024.

Answer 1

You may have to uncomment pam_limits.so from the different files under /etc/pam.d (cron, su, sudo, sshd, login)

session    required   pam_limits.so