Re: FreeBSD 8.0 - network stack crashes?

2009/11/30 Eirik Øverby <ltning_at_anduin.net>:

>> That URL works for me. So how much traffic is this box handling during
>> peak times?
>
> Depends how you define load. It's a storage box (14TB ZFS) with a small handful of NFS clients pushing backup data to it .. So lots of traffic in bytes/sec, but not many clients.

Ok.

> If you're referring to the Send-Q and Recv-Q values, they are zero everywhere I can tell.

Hm, I was. Ok.

>> See if you have full socket buffers showing up in netstat -an. Have
>> you tweaked the socket/TCP send/receive sizes? I typically lock mine
>> down to something small (32k-64k for the most part) so I don't hit
>> mbuf exhaustion on very busy proxies.

> I haven't touched any defaults except the mbuf clusters. What does your sysctl.conf look like?

I just set these:

net.inet.tcp.sendspace=65536
net.inet.tcp.recvspace=65536

I tweak a lot of other TCP stack stuff to deal with satellite
latencies; its not relevant here.

I'd love to see where those mbufs are hiding and whether they're a
leak, or whether the NFS server is just pushing too much data out for
whatever reason. Actually, something I also set was this:

# Handle slightly more packets per interrupt tick
net.inet.ip.intr_queue_maxlen=512

It was defaulting to 50 which wasn't fast enough for small packet loads.



Adrian