ulimit命令使用

查看某个进程当前 ulimit 所有设置:

cat /proc/<pid>/limits

永久修改某个用户或组的配置，见文件 /etc/security/limits.conf

可以通过 lsof -p 查看进程打开文件数

Linux/Centos/RHEL的进程限制，打开文件描述符限制配置

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.

*                soft    nofile          65536 
*                hard    nofile          655360  
*                soft    nproc           65536 
*                hard    nproc           65536
*                soft    memlock         unlimited 
*                hard    memlock         unlimited

Also check the settings in above file:

/etc/security/limits.d/90-nproc.conf