I am using debian version 7.4
The /etc/pam.d/su file there
does not enable pam_limits.so
the snippet is:
# Sets up user limits, please uncomment and read /etc/security/limits.conf # to enable this functionality. # (Replaces the use of /etc/limits in old login) # session required pam_limits.so
Why is that ?
googling for it, got articles like
On some systems the pam module called pam_limits.so is not set in the file /etc/pam.d/su. When it is not set, it prevents the conveying of limits (such as open file descriptors) to any command started with su - In particular, the HP Vertica init script would fail to start HP Vertica because it calls the Administration Tools to start a database with the su - command. This problem was first noticed on Debian systems, but the configuration could be missing on other Linux distributions. To resolve this issue, modify the install_vertica script and append this line to the /etc/pam.d/su file: session required pam_limits.so