There is no user interaction possible with the dual DOMs as the appliance defaults to loading its OS from DOM1 and if this fails it'll try the second. We tested this by physically separating the two DOMs and booting the appliance only with the primary device plugged in.
This worked fine but when we swapped it over with the secondary DOM we found that many of our configuration settings were missing. The RAID array was fine and had all our own folders and shares on it but a number of network services had stopped and all users, groups and AD settings were gone.
In the event of a boot failure the dual DOM will get essential storage back online but don't bother using the configuration backup facility as this doesn't include details of existing users and groups.
The N5500 certainly offers some unusual features and teams these up with a reasonable performance and a fresh new web interface. Business won't be overly impressed with the backup features, which are easily bettered by Netgear's ReadyNAS business appliances but the dual DOM isn't a bad idea as it'll get your storage back up in the event of a primary boot device failure.
Verdict
The N5500 offers businesses plenty of storage capacity along with good access security. Backup features are very basic but the spruced up web interface will make management easier and the dual DOM can get your critical storage back online in the event of a boot device failure.
Chassis: Desktop
CPU: 1.86GHz Celeron M
Memory: 1GB 667MHz DDR2 SO-DIMM
Storage: 2 x Afaya 128MB IDE DOMs; 5 x hot-swap SATA drive bays
Ports: 5 x USB2 host; USB2 device; eSATA
Network: 2 x Gigabit Ethernet
Software: Setup Wizard, Backup Utility and FarStone DriveClone Pro
