single VS distributing new connections across multiple pools with persistence

There can only be one default pool associated with a virtual server. This default pool would be used if the rule didn't specify a new pool. The persistence cookie has an encoding of the pool member IP:port. So consider the following scenario:

 

 

1. a client is selectively load balanced to pool2 member 1.1.1.1:80 by an iRule

 

2. client receives a persistence cookie from the persistence profile for 1.1.1.1:80

 

3. client makes a new request to the virtual server with the persistence cookie for 1.1.1.1:80

 

4. if the iRule doesn't select pool2, LTM would not know to automatically select pool2 and pick the original member

 

 

You can test this to confirm.

 

 

If you can guarantee pool1 and pool2 would never have a pool member in common, I suppose you could decode the IP:port from the cookie, check to see if the IP:port is a member of pool2 and then use pool2. But I think it would be much easier to use a separately named persistence cookie for each pool and select the pool based on the presence of the persistence cookies.

 

 

Aaron