RHEL6 64 bit Kernel Parameter Tunning

This table shows the parameters tuned on RHEL6 64 bit machines to meet our need in SLAC for accelerator controls.

 

 

parameter what for default how to overwrite how to verify set for production how to mintor
nproc to limit the number of processes (processes + threads forked)
that a user can run.
1024 /etc/security/limits.d/90-nproc.conf ulimit -u * soft nproc 405504

ps -L -u jingchen | wc -l

Note: -L option to include threads forked by processes.

Showing the total number of processes ( processes + threads forked) a user is running.

nofile to limit the number of FDs that a process for a user can open. 1024 /etc/security/limits.conf ulimit -n * soft nofile 8196
* hard nofile 16384
ls /proc/PID/fd/ | wc -l
file-max Maximum number of FDs for the entire system dynamic /etc/sysctl.conf

cat /proc/sys/fs/file-max

 

Use the default.

Can be reset as

fs.file-max=xxxx

in /etc/sysctl.conf

cat /proc/sys/fs/file-nr

Note: the first number shows the total allocated FDs; the last shows
file-max

threads-max Maximum number of threads to be used by the kernel (system-wide) at one time. dynamic /etc/sysctl.conf cat /proc/sys/kernel/threads-max

Use the default.

Can be reset as

kernel.threads-max = 811008

in

/etc/sysctl.conf

cat /proc/loadavg

Note: The fourth field consists of two numbers separated by a slash (/). The value after the slash is
the total number of threads running.

 

Note: on SLAC tailored machines, /etc/security/limits.conf is redefined by Tailor, setting

* soft nofile 8196
* hard nofile 16384

 

Created by Jingchen Zhou, 08/13/14