BUYER’S GUIDE: Know your NAS
The term NAS covers a huge gamut of devices. To help whittle down your options, we provide the questions you need to answer
What do you need a NAS for?
If you’re buying a NAS for business backup and file-server duties, you don’t have the same requirements in terms of processing power and connectivity as someone wanting a 4K video-streaming media server. If your needs are simple, spend less on the NAS and more on the hard disks it will use for storage. If you know you want to do more – or just plan to see what a NAS can do – then invest in the best NAS you can afford, even if that means a two-bay device. Talking of which…
Two-bay or not two-bay?
Don’t dismiss two-bay NAS devices. You can buy one with between 2TB and 12TB of storage built-in or choose a barebones NAS or enclosure and fit your own drives. 8TB drives are now widely available, giving you up to 16TB of space.
But there is a counter-argument: with a four-bay NAS, you can take full advantage of RAID. In a simple RAID0 or JBOD (“just a bunch of disks”) configuration, you get the full capacity of each drive, but you’re missing out on one of the key benefits of NAS: redundancy. With a RAID1 configuration, any data you copy to the NAS is mirrored across both drives, giving you a backup if one fails but halving the effective capacity. It means that an 8TB NAS will deliver roughly 4TB of space.
That’s where the benefits of a four-bay NAS come into play. With four drives in a RAID5 array, you use one of your four drives as a parity drive to offer the same data protection as RAID1, but without halving the capacity. You only lose one drive’s worth of capacity, plus a 10% to 15% overhead, meaning you still keep approximately two-thirds of the capacity available for use.
Four-bay appliances tend to use more power than two-bay appliances, so factor in your overall running costs. 10W here and there makes a difference with a device that’s designed to run 24/7, although sleep modes and hibernation modes will help reduce power usage overall.
“Fitting drives is mostly easy, thanks to slide-out, tool-less caddies that enable you to fill a four-bay NAS in under ten minutes”
Barebones or built-in?
This boils down to convenience and cost. Buy an enclosure-only or barebones NAS and you’ll need to purchase and fit the drives yourself. Fitting drives is mostly easy, thanks to slide-out, tool-less caddies that enable you to fill a four-bay NAS in under ten minutes. What’s more, it’s nearly always cheaper to take this approach, and you can look around for the best deal on drives and the enclosure.
However, some manufacturers sell a pre-filled NAS at surprisingly competitive prices, and you have the advantage that the NAS comes ready to go and that there’s only one point of contact should the NAS or a drive fail.
ARM or Intel? Dual-core or quad-core?
Beyond capacity, the biggest difference between a budget NAS and a high-end unit is processing power. A NAS is effectively a simplified Linux-based microserver, and the more users it serves and more demanding the applications it runs, the more processing power it’s going to need. If you’re simply running a daily backup to one or two PCs, this isn’t much. But, when you have several users copying or accessing files stored on the NAS, slow transfer speeds and latency come into play.
Throw in higher-end applications, such as media transcoding and cloud-like sync services, and your processor requirements grow. Given this and the affordability of a well-specified NAS, we would recommend avoiding anything with a single-core CPU and less than 1GB of RAM. Dual-core and quad-core ARM-based processors should be fast enough for small businesses, homes and mainstream applications, but may be stretched by more users or heavier workloads. That’s where Intel dual- and quad-core Celeron processors prove their value, handling tougher workloads or transcoding 4K video without breaking a sweat.