I've built two machines so far with the 1.5 BETA code and I've noticed
a strange problem that keeps cropping up in my 1.5/RAIDFrame system.
(Celeron, Asus + onboard i82557, 256 MB RAM, Two identical 10 GB
fujitsus.)

Specifically, under certain loads (75 concurrent connections totalling
300K/sec on 100 Mbit line) the transfers become very "bursty". High
troughput for a moment, then a pause, then repeat. I've examined the
traffic and there is no packet loss.

I've been combing through the mailing list archives--and I've tried
tuning various sysctl variables such as tcp.recvblah and
tcp.sendblah to as much as 65K and as low as 16K, and there is no
difference.

I've tried to look for problems with this type of network
card--nothing so far except that the card is difficult to program for.

I've increased NMBCLUSTERS to 8196 via gdb --write /netbsd, etc.

I've modified my ftp daemon (proftpd in my case) to use large, then
small receive and send buffers.

I've turned on, then off the Nagle algorithms.

I've turned on, then HURRIEDLY turned off net.inet.tcp.cwm.

I've turned on, then off newreno.

I've tried various combinations..

When I first built the machine it was running at a good clip--well
over 8 MB/sec downloads to a single client, and a speedy, handy
response time.

Now that it's under a light load, though, performance is just a
little.. off? CPU is sitting at 98% idle.. lots of free memory..

Can you think of any suggestions for me? Shall I convert back to a
primary drive that's just mirrored every night to a second drive in
case of failure?

Thanks,

Marc