I always get a bit confused on this behavior sometimes. So If I add a new Lun to an esx host, the device will show up on all the HBA adapters on all other esx hosts in the Cluster(s) that are zoned to this particularly arrary---within about 5min. I do not need to rescan hbas to find the new device.
Next when I actually create a vmfs volume from one of the hosts, in order to get that vmfs volume to show on the other hosts---I can either do a Refresh datastore from Vcenter storage pane on the hosts, or rescan just one of the host HBAs looking for new VMFS.
With over 100 Luns on each host, I always try to avoid an hba rescan--as it seems to knock the host cpu up. And Refresh datastores seems to work. Which is preferable?
Additionally, is there a default scan that happens infrequently that might let the hosts pick up the vmfs datastores not their own? Say if you left it alone for an hour or too?
Curious questions,,,