Questions and Answers

Amy Rich

Q. I want to set up IP Multipathing on my Netra T1. I’ve heard it’s now possible with Solaris 8, but it doesn’t seem to be well covered in the docs. Any pointers?

A. First, be sure that you have have media dated 10/00 or later; that’s when multipathing was introduced. There are several reference documents that will be of use to you.

• An article on the blueprints site: http://www.sun.com/blueprints/0801/Multipathing-updt1.pdf

• The IP Network Multipathing Administration Guide: http://docs.sun.com/ab2/coll.780.2/IPNETMPADMIN/

• A Sys Admin article written by Peter Baer Galvin: http://www.samag.com/documents/s=1441/sam0111i/0111i.htm

• A short HOW-TO style document, by Doug Hughes: http://www.eng.auburn.edu/~doug/howtos/multipathing.html

The basic steps are:

1. Make sure you have two working NICs in your machine (the Netra T1 comes with two already, so you should be fine there).

2. Configure the machine to use actual Ethernet addresses by doing:

eeprom 'local-mac-address?=true'

3. Obtain four IP addresses (two floating public addresses, one for each NIC, and two fixed private addresses, one for each NIC).

4. Create /etc/host entries for all four IPs, tying the actual machine name to one of the public IPs.

5. Set up the secondary interface to use a different MAC address.

6. Create /etc/hostname.<interface> files according to the hostnames you defined in /etc/hosts.

7. Tweak failover parameters in /etc/default/mpathd.

If you’re using more than two NICs, be sure to take that into account for the above numbers (two IPs per NIC).