HI ,
As part of best practice take full Back up of all vms in some other location .
1.Disable HA&DRS from vCenter (There won't be any vmotion of vms to another rhost )
2 Shut down all VM in all hosts /cluster/
3 Enter 1 host in maintenance mode.
4 Enter 2 host in maintenance mode.
4. Shut down 1 host
5. Shut down 2 host.
Verify that MSA having latest firmware of SP in that follow the proper steps HP recommends like update make 2nd SP and Primary , upload file , do update
Then after some work on disk storage HP MSA (disks firmware upgarde - which I'm afraid doing because dataloss)
Refer # http://h20564.www2.hpe.com/hpsc/doc/public/display?docId=mmr_kc-0121439
6. Power on host 1
7. Power on host 2
8. Exit maintenance mode host 1.
9. Exit maintenance mode host 2 .
10. Verify that all luns are presented and working normal before powering on all VMs
Note # make sure your server also having latest firmware and drivers , if not please do update of same before putting the server in to production that you may do one by one .
Run the infra on one server and do update another host and vise versa