Resignaturing requires to re-register all VMs on that datastore, i.e. downtime for all VMs on the datastore, and possible administration requirements for VM based backup applications.
What type/model of storage do you use. Some storage vendors provide additional software packages for ESXi to ensure that the LUNs are mounted properly after a reboot.
XIOtech ISE 2 SAN with dual connections to both hosts. I've had this particular setup since vSphere 5 and have upgraded to 5.5 and then to 6.0 without any issue. Not sure what happened with this 6.5 upgrade. I really don't want to go through the trouble of re-signaturing if I don't have to.
Please check the firmware and driver version of controller , if it is outdated one update to latest one .