FreeBSD 8.0 - network stack crashes?

[Eirik Øverby]

On 30. nov. 2009, at 09.50, Adrian Chadd <adrian at freebsd.org> wrote:

> 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

I fact it's mostly receiving. Other boxes on the LAN (or other  
internal subnets) are pushing data to it, rarely reading any except to  
check status and clean up.


> 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.

I'll try all those and then some, but I'm no optimist.. Might try on  
different hardware later.

Thanks,
/Eirik


> Adrian
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