Upgrade esxi hosts with SAN.

Hi Experts,

While upgrading / Installing ESXi hosts from 5.5 to 6.5 which are using SAN(HBA's), is it necessary to detach the fibre before continuing with the upgrade?

Will the datastore's content be wiped-off if we do not detach?

I will be using update manger OR esxcli for upgrade.

Thank you.