Which NAS?

Late last year I was commissioned to write a group test of NAS systems intended primarily for Time Machine network backups. I’m delighted to report that my review has now been published, in two of Future’s magazines, MacFormat (issue 376) and Mac|Life (issue 191). These are both print magazines, with electronic editions available through their apps in the iOS/iPadOS App Store, and my review won’t appear online. This article provides some additional information to that in the magazines.

Products not available

I’ve been writing and reviewing products for Mac magazines for well over thirty years now, and this is the first time that I’ve had manufacturers refuse to provide their products for review. The five whose NAS systems I tested were really keen, and although the Mac market may be relatively small compared to their total sales, all five want to be competitive in this market.

The surprise here was one manufacturer which I had thought valued its Mac market, and was keen to compete for it. However, for the moment they don’t seem interested in reviews which compare their NAS systems to those of their competitors. You shouldn’t find it hard to work out who they are from the list of products I reviewed. If you’re thinking of buying a NAS from a vendor not included in the five in my review, then you might like to think again.

Performance testing

The comparison table in my article has been greatly condensed from my original, and doesn’t include the results of the performance testing, which took many days. Given the previous discussions here, it may be useful to see some figures.

I performed three types of test. The first was a full Time Machine backup of a reasonably basic Data volume. When you first configure a NAS into a RAID mirror, its disks are ‘synchronised’, which takes a day or so, depending on the capacity of the hard disks. I therefore waited until that synchronisation was complete, and analysed the first full backup, and one standardised incremental backup after that. I used T2M2 to discover the quantity of data copied in each backup, and the time required, from which I derived an overall backup rate in MB/s.

The range of backup rates for the first full backup was 29-35 MB/s, with the leading systems all between 32-35 MB/s. There was thus little to choose between them in this respect. The incremental backup was slightly faster, with a range of 31-43 MB/s. The only performance which stood out there was backing up to the networked M1 Mac, at 43 MB/s, leaving the NAS systems more uniform at 31-37 MB/s.

The second performance test was copying a single 10 GB file to and from the NAS in the Finder. Three systems performed best at those: Asustor, Synology, and the M1 Mac mini, and the TerraMaster was slower than the others. Highest transfer rates were just over 100 MB/s, and the lowest a mere 24 MB/s. The weakest performer here, the TerraMaster, is due a software update which I suspect will produce significant improvements. What is also notable here is that these Finder copies of single files were achieved three times faster than those of Time Machine backups, and close to the maximum possible over a standard ethernet connection.

The third performance test was the unkindest of them all: I ran my disk performance benchmark tests in Stibium, which was developed to test internal SSDs in M1 Macs. Results impressed me, as most of the NAS systems came quite close to their performance on the single large file. Best all-round performer here was the Synology, which recorded 94 MB/s writing to the NAS and 99 MB/s reading. I gather that Synology has recently updated its software to improve transfer speeds over SMB, which may explain this.

SMB isn’t slow, at least in macOS Monterey, and you shouldn’t have to fiddle with obscure options to achieve good performance.

Is a NAS a good option?

Although I still believe in the benefits of local storage for backups, I appreciate that for many, being able to back up over a network is a great advantage. While that’s not the fastest option, it has virtues which make it highly attractive. Each of the six systems I compared in my group test would make excellent network storage, and I’m sorry to have sent the five NAS systems back to their manufacturer. Without exception.

Existing NAS users don’t always explore available apps either. Several have asked me here about features such as Spotlight on networked storage, when most of those systems offer their own search software. For those who want to run Intel versions of Windows but have an Apple Silicon Mac, virtualisation is possible on several of the systems I tested, and an option worth investigating further.

Which NAS to replace a Time Capsule?

Any of the NAS systems I reviewed would make an excellent replacement for a Time Capsule. Although you’d need to provide your own Wi-Fi network, that’s better done in separate hardware anyway. These systems let you choose your own disks, decide whether to configure them in a RAID array, and can expand their storage using external disks as well.

None of them is as simple to set up as a Time Capsule, but they don’t require use of the command line, knowledge of Linux, or even understanding of their internals. Instead, they are set up using your browser, using a full GUI, usually in a matter of minutes. Given their capacity, power, flexibility and modest cost, they make ideal replacements.

If you’re still using a Time Capsule, it’s already long past its fail-by date. It’s high time that you replaced it before it made that decision for you. There’s an excellent choice of NAS systems from these manufacturers. In each case, they are but one model from a range of different products, and your choice is wide. All you have to do now is pick one and order it.


The same issue of MacFormat has two other sections that I wrote: its cover feature is a compilation of 85 troubleshooting tips for macOS, iOS and iPadOS forming a unique reference, and there’s my regular monthly Genius Tips. I expect that Mac|Life also carries both of those too.