so had this issue on one of my hosts
reboot did the trick (had no other option though) and doing so even found all my new datastores I was scanning for in the first place.
of course the other host was still showing connected in vSphere client so I didn't check it. Went to rescan the host that didn't freeze up yesterday to add some datastores and it failed. Found several dead or error / lost comm devices in iSCSI adapter. Specifically, I received these two errors
Call "HostStorageSystem.RescanAllHba" for object "storageSystem-4744" on vCenter Server "vc.domain.local" failed.
Call "HostDatastoreSystem.QueryAvailableDisksForVmfs" for object "datastoreSystem-4744" on vCenter Server "vc.domain.local" failed.
how can I remove those targets without rebooting the host? Even if I can remove them manually, will rescanning all HBAs work or is a reboot inevitable? I might like to reboot to "freshen" things up but don't want to until next week sometime, if possible.