[olug] Facebook developers in Omaha? and some sysctl.conf stuff

[George Neill]

Adam,

Obligatory Linux stuff:
> I'm currently using this /etc/sysctl.conf on some of my webservers for
> performance purposes. Any one else have some nice /proc tweaks they'd like
> to share?
>
> net.ipv4.ip_forward = 0
> net.ipv4.conf.default.rp_filter = 1
> net.ipv4.conf.default.accept_source_route = 0
> kernel.sysrq = 0
> kernel.core_uses_pid = 1
> net.ipv4.tcp_syncookies = 1
> kernel.msgmnb = 65536
> kernel.msgmax = 65536
> kernel.shmmax = 4294967295
> kernel.shmall = 268435456
> net.core.rmem_default = 524288
> net.core.rmem_max = 524288
> net.core.wmem_default = 524288
> net.core.wmem_max = 524288
> net.ipv4.tcp_wmem = 4096 87380 524288
> net.ipv4.tcp_rmem = 4096 87380 524288
> net.ipv4.tcp_mem = 524288 524288 524288
> net.ipv4.tcp_rfc1337 = 1
> net.ipv4.ip_no_pmtu_disc = 0
> net.ipv4.tcp_sack = 1
> net.ipv4.tcp_fack = 1
> net.ipv4.tcp_window_scaling = 1
> net.ipv4.tcp_ecn = 0
> net.ipv4.route.flush = 1
> net.ipv4.tcp_timestamps = 0
> net.ipv4.tcp_keepalive_intvl = 30
> net.ipv4.tcp_keepalive_probes = 5
> net.ipv4.tcp_tw_reuse = 1
>

back in the days, I had tuned,

net.ipv4.tcp_fin_timeout*

*to fight off a bunch of lingering FIN_WAIT2's for heavy traffic web sites.
Not sure if it's relevant today ... the defaults are usually pretty good.*
*
Will you guys be supporting ipv6 anytime soon?  If so, have you (or anyone
else) tuned for or had issues with ipv6?

Later,
George