performance tuning of iSCSI and Dell MD3000i

[Miroslav Lachman]

Andrew Snow wrote:
>
> Hi Miroslav,
>
> have you tried increasing your TCP/IP Window settings at both ends?
>
> In freebsd sysctl.conf:
>
> kern.ipc.maxsockbuf=1048576
> net.inet.tcp.recvspace=262144
> net.inet.tcp.sendspace=262144
>
>
> I never had trouble hitting line rate of 1Gbps iSCSI with freebsd, but
> the biggest problem was not speed but what happens if the device times
> out or drops out, it causes FreeBSD to completely crash instead of
> degrading gracefully.

My current settings is:

kern.ipc.maxsockbuf: 262144
net.inet.tcp.recvspace: 65536
net.inet.tcp.sendspace: 32768

net.inet.tcp.recvbuf_max: 262144
net.inet.tcp.recvbuf_inc: 16384
net.inet.tcp.recvbuf_auto: 1
net.inet.tcp.sendbuf_max: 262144
net.inet.tcp.sendbuf_inc: 8192
net.inet.tcp.sendbuf_auto: 1

I will try your recommended values and post results later this day.

(but I don't know how can I change it on MD3000i side)

Thank you for your reply

Miroslav Lachman