[OpenIndiana-discuss] Are there any known problems with OI and jumbo frames MTU 9000

[Jim Klimov]

On 2013-01-18 09:22, Flo wrote:
> Why do you use a MTU of 9000? Only for the higher performance or for the
> lower CPU load?

Basically, because we can ;-\
I don't remember really benchmarking before and after; it was just a
recommendation we followed when I was young and tuned that network:
bulk data and database IO which stayed inside the LAN were published
on both a legacy net and on a private jumbo vlan for hosts with shiny
new gigabit interfaces.

> Hi Jim
>
> thank you for your advice!
>
> I don't know, if the broadcom nics are powerfull enough?
> I tested the throghput with iperf with MTU 1500 and MTU 9000.
> With 1500 I got 945Mbit and with 9000 I got 985Mbit.
>
> With the newest Solaris version, there is no need to edit the driver
> config file. Is this also possible with OIa7 or is it possible to
> activate the new config file without a reboot?

FWIW, on a Solaris 10 Sun V240 I see this config tweak in bge.conf
(back then Broadcoms were the brand of choice for Sun):

# diff bge.conf-*
157,170d156
< # see http://www.opensolaris.org/jive/thread.jspa?messageID=48569
< # http://www.sunmanagers.org/pipermail/summaries/2003-December/004776.html
< # 
http://blogs.sun.com/shantnu/entry/opensolaris_project_brussels_unified_nic
< #default_mtu=9000;
< #default-mtu=9000;
< #default_mtu=8000;
< default_mtu=1500;
<
< # interface bge0
< #name="bge" parent="/pci at 1f,700000" unit-address="2" instance=0 
default_mtu=1500;
< #name="bge" parent="/pci at 1f,700000" unit-address="2" instance=188000 
default_mtu=9000;
<
< # interface bge3
< name="bge" parent="/pci at 1d,700000" unit-address="2,1" default_mtu=9000;

and in /etc/hostname.bge3 it spells "mtu 9000" after the node name.