dont think anyone can guarantee zero downtime, for every 9 you add the cost exponentially grows tho.
Application HA sounds good, I dont have any experience with it but all that does is restart a service(s) so if there was an issue and worst case restarts the server, you would still get some downtime. not sure how this would work in a clustered solution or if it even does, but either way its not going to be zero downtime
FT and MSCS dont work together. and FT comes with the limitation of only allowing 1vcpu so that limits the larger apps i guess.
MSCS with VMware HA is a pretty good combo and same with NLB clusters if they are hardware load balanced. but again there is always the failover point when your offline weather its application HA restarting the service to restore it, or MSCS failing over resource, of HA powering back up a machine etc etc etc.
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VCDX #201
Author of Mastering vRealize Operations Manager
