increase ulimit open file

How to increase ulimit open file and user processes in Linux/Centos/RHEL

Max Number of ulimit open file : It's provide open file resource availability in linux

Increase max number of ulimit open file in Linux.

1- Step :  open the sysctl.conf  and add this line  fs.file-max = 65536

vi /etc/sysctl.conf   add end of line
fs.file-max = 65536

save and exit.

2. Step : vi /etc/security/limits.conf  and add below the mentioned

*          soft     nproc          65535
*          hard     nproc          65535
*          soft     nofile         65535
*          hard     nofile         65535
save and exit check max open file ulimit
[root@localhost# 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) 127358
max locked memory       (kbytes, -l) 64
max memory size         (kbytes, -m) unlimited
open files                      (-n) 65535
pipe size            (512 bytes, -p) 8
POSIX message queues     (bytes, -q) 819200
real-time priority              (-r) 0
stack size              (kbytes, -s) 10240
cpu time               (seconds, -t) unlimited
max user processes              (-u) 1024
virtual memory          (kbytes, -v) unlimited
file locks                      (-x) unlimited

Increase max user processes in Linux

Follow the step:

vi /etc/security/limits.conf  and add below the menstioed

*          soft     nproc          65535
*          hard     nproc          65535
*          soft     nofile         65535
*          hard     nofile         65535
and  vi /etc/security/limits.d/90-nproc.conf

*          soft     nproc          65535
*          hard     nproc          65535
*          soft     nofile         65535
*          hard     nofile         65535
save and exit check the user max processes ulimit
[root@localhost# 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) 127358
max locked memory       (kbytes, -l) 64
max memory size         (kbytes, -m) unlimited
open files                      (-n) 65535
pipe size            (512 bytes, -p) 8
POSIX message queues     (bytes, -q) 819200
real-time priority              (-r) 0
stack size              (kbytes, -s) 10240
cpu time               (seconds, -t) unlimited
max user processes              (-u) 65535
virtual memory          (kbytes, -v) unlimited
file locks                      (-x) unlimited


After make changes need to reboot system.