Open Files Limit

# ulimit -Ha
time(seconds) unlimited
file(blocks) 2097151
data(kbytes) unlimited
stack(kbytes) unlimited
memory(kbytes) unlimited
coredump(blocks) unlimited
nofiles(descriptors) unlimited

# ulimit -Sa
time(seconds) unlimited
file(blocks) 2097151
data(kbytes) 131072
stack(kbytes) 32768
memory(kbytes) 32768
coredump(blocks) 2097151
nofiles(descriptors) 2000

nano /etc/security/limits.conf

* soft nofile 102400
* hard nofile 102400
* soft nproc 10240
* hard nproc 10240

Заместо * можно указать название сервиса

mysql soft nofile 102400
mysql hard nofile 102400
mysql soft nproc 10240
mysql hard nproc 10240