sysctl kern.ipc.somaxconn limit 65535 why?

Ryan Stone rysto32 at gmail.com
Wed Oct 3 22:03:50 UTC 2012


>> Or the TTL of TCP connections might be too high for the volume of
>> connections received. Someone else on net@ reported that changing
>> this value to more aggressively reap sockets improved performance
>> greatly (at the cost that more connections potentially needing to
>> be reestablished and/or getting dropped on the floor if things go
>> too high volume).
>
> That's a different topic I think.  On busy web servers it's fairly
> typical to have a lot of TCP sockets staying in TIME_WAIT state for
> extended time and the usual tuning would be to set MSL to about 2
> seconds at the expense of sacrificing slow clients who can't make
> 3-way handshake in time (*), etc.  The TTL of IP packet have nothing
> to do with this though, and our default (64) is saner than many other
> operating systems.

Presumably RTT was meant here instead of TTL.


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