topic Process restart after sysctl update in Operating System - Linux

Process restart after sysctl update

Mick Ryan — Tue, 03 Mar 2009 14:50:28 GMT

All

I appreciate that you don't need to restart the O/S after making an update using the sysctl command. However, is it necessary for any processes to be restarted to pick up the new value?

For example, if I change tcp_syn_retries from 5 to 50, will that affect all processes or would they need to be stopped and started again?

Cheers

Mike

Re: Process restart after sysctl update

Steven McCoy — Tue, 03 Mar 2009 15:20:11 GMT

Hey Mick,

As far as my experience goes, sysctl updates do not apply to existing sessions. So I believe you need to start a new user session to take advantage of the new settings, requiring process restarts.

Re: Process restart after sysctl update

Mick Ryan — Tue, 03 Mar 2009 15:24:52 GMT

Thanks Steve,

Just found out that all the processes will get restarted overnight anyway. However, it's still an interesting question that I could see myself coming back to

Cheers

Mike

Re: Process restart after sysctl update

Heironimus — Tue, 03 Mar 2009 15:55:38 GMT

It depends on the setting. Some that affect per-process values will require that processes be restarted. My experience so far has been that a lot of the network-related settings only apply to new connections, but you don't have to restart any processes.