External musings
Full specifications for the N5500 are available here. The appliance, which can also function as a DAS and IP SAN, is compatible with Windows, Linux, Unix, and Mac OS9/X, so most folk will be covered.
The messaging that sticks out on the packaging is 'Dual DOM'. The Dual Disk-On-Module (DOM) is designed to add an element of redundancy to the NAS by having two disk modules instead of the usual one.
The modules house the operating system that boots and runs the N5500, and having a second one, which takes over should the primary DOM fail, makes some kind of sense. Thinking of it as akin to dual BIOSes on regular motherboards, one advantage may lie with having two different firmware versions that can be switched if matters go awry. Unforturtunately, the N5500 doesn't support it, at the time of writing.
The revised front makes the N5500 look sleeker. Somewhat strangely, open the door and you see that it blocks access to the power and rest buttons down the left-hand side, as shown below.
The five-bay NAS, housing 3.5in drives, looks awfully similar to the previous models once the door has been pulled aside. Indeed, it goes all the way back to the N4100, from four years ago.
Supporting JBOD and RAID 0/1/5/6/10 modes with hot-swap, auto-rebuild, and on-the-fly RAID migration, the basic feature-set is solid. iSCSI initiators are also supported, meaning the box can accept transfers as an iSCSI target drive, but you need to setup the RAID volumes with the required amount of space.
The LCD is still the same and provides rudimentary data on the NAS' status. The LED lights are probably more usable, denoting potential problems with connections.
Around the back, the N5500 has multifarious connections that include two Gigabit ports (WAN and LAN); Serial; eSATA, and four USB ports (one of which is a type-B), in addition to the one at the front. Again, the advances of N5200 Pro are minimal, and both Gigabit ports support load-balancing and failover, as well as 802.3ad link aggregation.
The type-B USB port can be used to make the appliance a USB-connected NAS, and eSATA provides a means of adding more external storage, should the five bays not be enough.
