NAS devices differ in more than just their usability. Another important aspect to consider is the number of hard drives you can add to your appliance of choice. This is especially crucial if you want to run your hard drives in a RAID configuration. Of course, NAS devices with two hard drives can only support RAID modes 0 and 1.
Which RAID Modes Do Home Users Need ?
In a RAID 1 configuration, the data from one hard drive is mirrored onto the other in real time, so it won’t be an issue of information loss should one of the hard drives die, as long as you replace it in a timely fashion. In RAID 0 mode, both physical hard drives are combined into one logical hard drive with data split up and distributed over the hard drives. The advantage of this is that read and write processes can be executed more quickly, but if either hard drive dies, all of your data is lost.
If You Want It Done Right, Do It Yourself
The DS207+ from Synology supports two hard drives, which can be operated in the aforementioned RAID 0 and 1 modes. But as opposed to the previously-introduced Maxtor Shared Storage II, the customer has to perform the configuration manually before the device is ready to use.
The DS207+ goes by the BYOD (bring your own drives) principle, costing about $329 without its own disks installed. This can be an advantage if you have unused hard drives laying around and you want to keep using them in a NAS device. But even if not, high-capacity storage is uber cheap right now, so you can add a pair of terabyte disks for right around $200 more. The maximum hard drive capacity that the DS207+ can handle is 2 TB, naturally.
In times of rising energy prices, operating cost becomes an important criterion. The amount of power that the DS207+ uses is low in comparison to full-size file servers: 33 watts during operation and 28 watts in idle mode. In sleep mode, with the hard drives turned off entirely, power consumption drops to just 11 watts.
Running the DS207+ 365 days a year, 24 hours a day (and assuming an average power consumption of 20 watts), the operating cost adds up to just under $45 for the entire year.