how to persist with cookie and improve rand() performance

Hi,dear irule

 

I have a pool test which has 10 pool members

 

1:when client visit this VS,if traffic go to node1 ,need to insert a cookie to it,during the same session,all request from has this cookie will be sent to the same node

 

 

how to achieve this?can some one give me an example of this?

 

 

2:according to test on rand(),I found rand() has bad performance than the irule without rand(),do anyone has idea how to improve it?

 

 

pls help me...

 

I need to use this in production