Recovery or test recovery fails with an error about host hardware and datastores being unavailable if you run the recovery or test shortly after changes occur in the vCenter Server inventory.

Recovery or test recovery fails with the error No host with hardware version '7' and datastore 'ds_id' which are powered on and not in maintenance mode are available....

Site Recovery Manager Server keeps a cache of the host inventory state. Sometimes when recent changes occur to the inventory, for example if a host becomes inaccessible, is disconnected, or loses its connection to some of the datastores, Site Recovery Manager Server can require up to 15 minutes to update its cache. If Site Recovery Manager Server has the incorrect host inventory state in its cache, a recovery or test recovery might fail.

Wait for 15 minutes before running a recovery if you change the host inventory. If you receive the error again, wait for 15 minutes and rerun the recovery.