HACMP with interfaces on the same subnet

[Ukyo]

Hi guys (+ gals),

this one is giving me a headache..
I have a two node cluster:
Node A
en0 service - 10.0.1.11
en1 standby - 10.0.2.11
Node B
en0 service - 10.0.1.12
en1 standby - 10.0.2.12

both en0's are on one switch (ie., 1.11, 1,12)
both en1's are on another switch (ie., 2.11, 2.12)

Let's say we have a failover, so on Node B we have:
en0 service - 10.0.1.12
en1 standby - 10.0.1.11 (failover from node 1)

As you can see, both interfaces are on the same subnet, we know that even without HACMP, AIX will choose en0 when the interfaces are on the same subnet. (why is this anyway? can it be set/changed?)

when switch X dies, en0 is dead. Why won't traffic go out from en1 on 1.11? How can I configure it to do so?

TIA!

Ukyo

 

[gileb]

first of all, it depends of your netmask... you can set your netmask to 255.255.255.0 or something approching, and it will be on different subnets.
Anyway when you set the default route, it will be on a gateway which should be in the same subnet than your prod adapter (en0) (also depends of your mask). If you dont set default route, you will not be able to join other systems that are on other subnets.
hacmp will have to be configured to handle en0 breakdowns, and therefore it will handle the default trafic and will config the en1 with 1.11. So you dont have to care about routes and theres a swap adapter.

hopes taht helps