I was hoping that using Solaris 10's jumbo frames would reduce Windchill's latency as seen by end-user's. I was surprised at how difficult it was to find consistent documentation and, in the end. disappointed that it did make too much difference. I am writing this blog in hope that it may help others to configure jumbo frames more quickly for similar experiments.
As stated by Wikipedia,, "In computer networking, jumbo frames are Ethernet frames above 1518 bytes in size. The most commonly supported implementations of hardware support for jumbo frames have a MTU of 9000 bytes. Jumbo frames, while sometimes used on a LAN, are rarely used when exchanging data, especially over the Internet."
In my test, I wanted to use jumbo frames for links "inside the data center". Specifically, for (1) the Sun Cluster interconnect between two V490 Sun Cluster Oracle RAC nodes, and (2) the communication between the T2000 application tier servers and the V490 database servers. The hope was that I would see a substantial reduction in the system time (i.e. CPU time inside the kernel) when few IO operations were required for a given payload. I did not attempt to use jumbo frames for the final HTML traffic to the end-users who would be "outside of the data center"..
The V490's Sun Cluster interconnect was via crossover cables, so the was no limit imposed by a router on the MTU size. The router between the application servers and the database servers advertised that it supported "8k" frames, so I set the MTU to less than 8192 bytes.
A) Configuring jumbo frames on the V490's
1) Find the path to the device:
# grep ce /etc/path_to_inst
2) Configure the ce driver:
3) set the MTU in the hostname file:
# cat /etc/hostname.ce0
scnode1 mtu 8168 group sc_ipmp0
4) Verify after reboot:
# ifconfig -a | grep mtu
mtu 8232 index 1
mtu 8168 index 2
9194 index 4
9194 index 3
mtu 9194 index 5
B) Configuring jumbo frames on the T2000’s:
1) Configure the e1000g driver
# grep MaxF /kernel/drv/e1000g.conf
2) Reboot and verify:
# ifconfig -a
flags=1000843<UP,BROADCAST,RUNNING,MULTICAST,IPv4> mtu 8168