Balancing two Front End to two Back End servers

For option 1, if you create two pools with priority group activation you'll get a simple iRule with low overhead.

Pool1  primary back1, secondary back2
Pool2  primary back2, secondary back1

Then in the iRule just split by IP of the incoming client to pool1/pool2.

when CLIENT_ACCEPTED {     
    if { [class match [IP::client_addr] equals "10.10.10.1"] } {        
        pool pool1             
    } elseif { [class match [IP::client_addr] equals "10.10.10.2"] } {        
        pool pool2             
    } else {        
        drop
    } 
}    

Something like that might work. Option 2 I'm not as familiar with catching the change in status using an iRule. Probably could be done easily.. I just haven't done it.

Jason