After upgrading host from 6.0 to 6.5 shared datastore (SAN) does not reconnect after reboot

[daccu]

After upgrading vCenter to 6.5 I went to upgrade the first host of a two-node HA cluster with a shared SAN from 6.0 to 6.5.  After the upgrade the host showed local storage but did not show the SAN as a datastore.  After doing a rescan for the datastore it appears and everything seems to work fine, that is until the next reboot and it is missing again.  I have read some people had luck re-adding the datastore with "assign new signature" (reference:  Datastore not mounted after reboot of ESXi5.5 ).  What is the impact of that method and could there be any other cause or solution?  Is the assing new signature an action on a single host, allowing our infrastructure to continue running on the other host, or does that require removing the datastore from vCenter and having to bring everything down?

[a_p_]

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.

André

[daccu]

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.

[admin]

Please check the firmware and driver version of controller , if it is outdated one update to latest one .