F5 GTM DNS persistence
Has anyone any experience in implementing dns persistence on the GTM's. We identified any issue with our current configuration and were recommended to split our LTM's from an active - Standby pair in to two independent LTMs'. Since doing this we've encountered problems with dns flipping during a session and redirecting a user to a different data centre and therefore a different sever. Before the change this didn't matter because we were using one pool and therefore one source ip persistence table so a user was directed to the same server not matter which data centre they connected in from. We have layer 2 links between our DC's so it possible for us to have servers located in different data centres in the same F5 pool.
To get around this problem we've been advised to use dsn persistence so a user will be directed to the same data centre if the dns ttl expires. Has anyone any experience with this and what are the potential problems we could encounter? I'm conscious we have no control over which dns servers a user hits so in my mind there're a chance a user could be still be flipped from one data centre to another which we cannnot afford.
To get around my problem I'm thinking of reverting back to an active - standby LTM set up. I can fool the GTM's in to thinking we have two active LTM's by NAT'ing a public ip address at each data centre back to the private real address of the LTM's. I would also need to NAT the source address of each GTM for iquery purposes. Would anyone know if NATing the source ip of the GTM could cause any problems with iquery.
Any advice very much appreciated as we seem to be implementing different fixes which in turn causes additional problems.