The best NAS hard drive

The best NAS hard drive is not easy to determine. Every NAS is different, everyone’s requirements are slightly different, too. The post: The most suitable NAS hard drive gives a first overview of the hard drives that are suitable for a NAS.

Which one is the best NAS hard drive?

Which one is the best NAS hard drive?

Personal Experience: My Best NAS Hard Drive

I have been building computers for more than 20 years and specialized NAS systems for about 10 years. A really best NAS hard drive didn’t crystallise itself in this time for me myself. I had countless hard disks from all three major manufacturers (Seagate, Western Digital, HGST) in my hands and no clear winner or loser turned up. In all that time, I only crashed one hard drive at a time. That was a Quantum Fireball in the late’ 90s. It was a really fast drive at that time, but it really started smoking and so it lived up to its name.

With all the other disks I noticed during operation, how the data accesses became slower and slower, or errors occurred frequently. I do not have an objective value at this point, but rather I have mostly assessed it subjectively. I replaced the drives before there were any problems.

Among the current models of NAS hard drives, I don’t really like a high reconnection count (4 / month) of 2 Western Digital Red disks in a Synology Diskstation. However, the disks still run perfectly (both 4 years old). And I find the HGST Deskstar NAS subjectively very fast, but also very loud. I don’t like the Deskstar NAS in a NAS that’s near my desk.

Real numbers

So, what’s the best NAS hard drive? Objective data can help. The Cloud service provider Backblaze is a good source of these objective figures – for the following reasons:

  1. Backblaze uses consumer drives for storage, as used in desktop or NAS systems for home use.
  2. They have tens of thousands of disks in use (as of mid-2017: more than 80,000).
  3. In their blog they regularly publish statistics on the error rates of the hard disks used.

The figures presented here are provided by this cloud service provider (see below for concrete sources).

For the aggregated statistics I only recorded drives that Backblaze used in 2016 (or earlier) and of which at least 1000 are in use. This way I was able to ensure that the results were not falsified with hard drives in short-term use or by a few samples.

The table of the best NAS hard drive

The following table shows the failure rates of the individual hard drive types in the last quarters and their mean values:

Drive Q1/2017 Q4/2016 Q3/2016 Q2/2016 Q1/2016 Average
HGST Deskstar 5K3000 3TB 0,95% 1,15% 0,35% 0,98% 0,53% 0,79%
HGST Deskstar 7K3000 3TB 1,74% 3,63% 1,20% 3,22% 0,81% 2,12%
Western Digital Red 3TB 1,15% 3,28% 2,21% 4,53% 3,09% 2,85%
HGST Deskstar 5K4000 4TB 0,16% 0,60% 0,30% 0,15% 1,05% 0,45%
HGST Megascale 4000 4TB 0,34% 0,51% 0,39% 0,11% 0,57% 0,38%
HGST Megascale DC 4000 4TB 1,41% 0,63% 0,55% 0,53% 0,00% 0,62%
Seagate Desktop HDD 4TB 3,27% 2,67% 3,18% 2,66% 2,54% 2,86%
Seagate Desktop HDD 6TB 0,67% 1,68% 0,64% 1,07% 0,00% 0,81%
Seagate Desktop HDD 8TB 1,03% 1,65% 1,46% 3,06% 1,80%

Curiously, Backblaze uses only one single type of large volume hard drive, known as “NAS hard disk“: The Western Digital Red 3 TB. Apart from the HGST Megascales, all other hard disks are “simple” desktop hard drives – and they run in 24-hour operation within large data centers!

The most important workhorse is the Seagate Desktop HDD 4TB with over 30,000 drives in use at Backblaze. Number 2 after that is the HGST Megascale DC 4000 with over 15,000 drives. The positive thing about the numbers is that they are fairly well assured. On the other hand, it says that Backblaze has been using the drives for a number of years, which means that most of the disks listed here are no longer available and are difficult to obtain.


The best NAS hard disk drive is, as with all complex decisions, a balance… if you can get a HGST Deskstar 5K4000, this is certainly not a bad choice. In general, the failure rates of HGST drives are generally very low. However, Backblaze would hardly use as many Seagate drives (approx. 60%) if they wouldn’t do their job well.

Western Digital does not appear to be well represented at first glance, but HGST was purchased by Western Digital in 2012 and subsequently had to hand over part of the 3.5″ drive production to Toshiba under pressure from the anti-trust authorities. With the new HGST hard disks, you won’t get any more from Hitachi’s production.

Data Sources

The data in this article are taken from various blog articles by Backblaze. In concrete terms, these are:

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