Need suggestions on selection of alternate pool

Let me make sure I understand. If a new connection has a persistence entry, then you want to do session persistence. However, you might want to send new connections to a different pool. Correct?

 

 

Write a load-balancing rule to choose the pool accordingly. Add a persistence profile to the virtual for the persistence mode that you want to use. Be sure to enable persistence across pools on the profile. I think the across pools option was tripping you up. Without it, we would create a new peristence entry if the load-balancing rule were to select a different pool for a connection that already had a persistence entry.

If you have hard limits on the number of connections each server can support, it is better to define these on the node definition. Use the Connection Limit setting. I try to use the iRules only when a standard feature can't do the job.

citizen_elah is correct. The connection limits only apply to the NEW connections that do not have a session persistence entry.

 

 

Using a different metric other than the number of connections is tricky because it's tough to inject metrics into the data-plane for LB decisions. You might be able to do this with dynamic ratio load-balancing. That is, you should be able to set the node ratio to zero if its max load is exceeded. If that is the case, the node won't be selected for new connections, but persistent connections will continue to use it. Note that this is different than marking the node down. You can direct traffic to a sorry page using either an LB_FAILED rule or an HTTP fallback host.

You should also read up on min active members.