====== User Limits ======
===== Check limits =====
List the limits values for a specific user
[root@lnx01]/etc/security # su - ispprod3 -c "ulimit -a"
core file size (blocks, -c) 0
data seg size (kbytes, -d) unlimited
scheduling priority (-e) 0
file size (blocks, -f) unlimited
pending signals (-i) 385914
max locked memory (kbytes, -l) 64
max memory size (kbytes, -m) unlimited
open files (-n) 8096
pipe size (512 bytes, -p) 8
POSIX message queues (bytes, -q) 819200
real-time priority (-r) 0
stack size (kbytes, -s) 8192
cpu time (seconds, -t) unlimited
max user processes (-u) 4096
virtual memory (kbytes, -v) unlimited
file locks (-x) unlimited
To list only hard limits : ulimit -Ha
To list only soft limits : ulimit -Sa
To modify a value for a specific user add the lines at the end
[root@lnx01]/etc/security # cat /etc/security/limits.conf
# -
#
#Where:
# can be:
# - a user name
# - a group name, with @group syntax
# - the wildcard *, for default entry
# - the wildcard %, can be also used with %group syntax,
# for maxlogin limit
#
# can have the two values:
# - "soft" for enforcing the soft limits
# - "hard" for enforcing hard limits
#
#
- can be one of the following:
# - core - limits the core file size (KB)
# - data - max data size (KB)
# - fsize - maximum filesize (KB)
# - memlock - max locked-in-memory address space (KB)
# - nofile - max number of open file descriptors
# - rss - max resident set size (KB)
# - stack - max stack size (KB)
# - cpu - max CPU time (MIN)
# - nproc - max number of processes
# - as - address space limit (KB)
# - maxlogins - max number of logins for this user
# - maxsyslogins - max number of logins on the system
# - priority - the priority to run user process with
# - locks - max number of file locks the user can hold
# - sigpending - max number of pending signals
# - msgqueue - max memory used by POSIX message queues (bytes)
# - nice - max nice priority allowed to raise to values: [-20, 19]
# - rtprio - max realtime priority
#
#
-
#
#* soft core 0
#* hard rss 10000
#@student hard nproc 20
#@faculty soft nproc 20
#@faculty hard nproc 50
#ftp hard nproc 0
#@student - maxlogins 4
# End of file
* hard core 0
ispprod3 soft nofile 16192
ispprod3 hard nofile 65536
Now recheck the soft limit for number of open files
[root@lnx01]/etc/security # su - ispprod3 -c "ulimit -Sn"
16192
Check which was the limit when a process was started by user
[root@lnx01 ~]# ps -ef | grep dsmserv
ispprod3 25949 1 52 Aug10 ? 1-10:05:39 /opt/tivoli/tsm/server/bin/dsmserv -i /ispprod3 -q
[root@lnx01 ~]# cat /proc/25949/limits
Limit Soft Limit Hard Limit Units
Max cpu time unlimited unlimited seconds
Max file size unlimited unlimited bytes
Max data size unlimited unlimited bytes
Max stack size 8388608 unlimited bytes
Max core file size 0 0 bytes
Max resident set unlimited unlimited bytes
Max processes 385914 385914 processes
Max open files 4096 4096 files
Max locked memory 65536 65536 bytes
Max address space unlimited unlimited bytes
Max file locks unlimited unlimited locks
Max pending signals 385914 385914 signals
Max msgqueue size 819200 819200 bytes
Max nice priority 0 0
Max realtime priority 0 0
Max realtime timeout unlimited unlimited us