ESXi

We are having an issue with one of the HBA's on a host within a 4-node cluster. Each host is currently using an average of 82.75% memory utilization. If I were to put the suspect host into maintenance mode for a reboot, I calculate the memory utilization to increase to 110% per host. This being the case, will I still be able to put a host into maintenance mode? Will the only consequences of doing this be poor performance due to memory swapping? Thank you in advance for your replies.

Yes by putting the host into maintenance mode  you will be creatinga situation that will put memory into contention and will affect the VM performance -

So vMotion will still work.. our VM's will just suffer from swapping and such.

It should work - but you can get into a situation where a host might not have sufficient resources and vmotion will fail -

Thank you for the reply weinstein5.