Persistence

OK, I'm not new here, but I've a few newbie questions unfortunately!

 

I've just been taking a very close look at all the persistence methods available for the first time really. I've nearly always used source or Cookie in the real world. What I'm confused about are the 'destination' methods, not Destination Address itself but others like; Universal, Hash and anything related to CARP.

 

So, source related methods like Cookie ensure multiple requests from the same client go to the same Pool Member. 1) With destination methods, the idea is to ensure the same request from multiple clients goes to the same Pool Member? 2) Presumably if that's the case then these methods are not suitable for applications that require session state?

 

3) Moving onto the Universal method, assuming I'm correct regarding 1) and 2) this uses the iRule specified data to create the persistence (record) and any client information is ignored (unless it's part of that iRule specified data)? Any requests from other clients that hold the same data go to the same Pool Member, if there's no existing persistent record, normal LB'ing occurs.

 

4) Moving onto Hash, it look similar but it's a hash value, not the actual data? 5) Are persistence records created? 6) If so, I assume normal LB'ing occurs once and the record is created? This is where I get really stuck. 7) Things like CARP seem to be selecting a Pool Member so does 'normal' load balancing never occur?

 

Thanks in advance.