Review – Upgrading to 10TB Seagate IronWolf 3.5-inch NAS Drives in a Seagate 4 Bay NAS Pro

It might be common sense that hard drives continually increase in size, speed, and reliability, but when to upgrade is a different sort of question when upgrading the drives in your NAS. The easy part is deciding that it’s time for more capacity, but what drives to use and how it works in practice are a bit more complicated a choice. We were curious what the recent upgrade of Seagate’s NAS drives to the new IronWolf series would mean.

Several years ago we reviewed the new Seagate NAS Pro series of NAS devices. The units we received were populated with Seagate 4TB NAS HDD drives. These worked fine, with only one drive that started to show some errors, but nothing serious. Still, when I reported those to Jon Bauder of Seagate’s Tech Support team, he arranged for an advance swap, so that I could use my credit card as a deposit on a new drive, to minimize downtime when the NAS would be missing a drive. The swap was easy, no hassles, although I was grateful to the well-written tech support guide for the proper process. The swap took minutes, just pull out the plastic drive carrier, exchange drives, and then login to the NAS via Seagate Network Assistant, and tell it to repair the missing drive, which takes about 5 mouse clicks. Then you wait, in the case of the 4TB drive, it took about 6 hours for the drive to be formatted, and then populated with the data from the rest of the NAS.

Over the past few years we have tested the Seagate Enterprise Capacity Drives in 4, 6, and 8TB capacities for our RAID systems using SoftRAID, but we hadn’t touched the Seagate NAS Pro units. So, when Seagate offered to update the drives to their newly announced Iron Wolf NAS drives, we thought it was a great idea. Originally we were going to use their 8TB drives, but in the past few months the newer 10TB versions have become available, so we made the jump to the new drives.

When we read the press releases on the new drives, it was easy to wonder if aside from the snappy new name and logo how much had changed. Plenty it turned out. When we first tested them with disk speed apps, I was certain something had gone wrong. They weren’t a little bit faster than last year’s models they were actually much faster! The drives were so much faster than I expected that I wrote to Seagate to confirm the findings. And it turned out that the numbers we were seeing weren’t an anomaly.

For some transfer rates consider the following results using the Black Magic Design Disk Speed Test:

6TB Enterprise Capacity HDD            106.4 Write / 102.9 Read            (Single Drive)

8TB Enterprise Capacity HDD            171.3 Write / 172.1 Read            (Single Drive)

8TB Enterprise Capacity HDD            161.8 Write / 215.9 Read            (SoftRAID Two Drive RAID)

Ok, till now the speed gains are steady and predictable, with a significant jump in Read Speeds using SoftRAID with multiple drives. Here is where it gets interesting with the new IronWolf 10TB drives.

10TB IronWolf NAS HDD                        240.7 Write / 240.5 Read            (Single Drive)

10TB IronWolf NAS HDD                        221.0 Write / 238.0 Read            (SoftRAID Two Drive RAID)

Using AJA System Test 2.1 revealed similar numbers:

8TB Enterprise Capacity HDD            132 Write / 170 Read                        (Single Drive)

10TB IronWolf NAS HDD                    217 Write / 238 Read                       (Single Drive)

Naturally the results will vary depending on the routine and app, but the speed gains in the new IronWolf series were significant.

Why did the drives perform so much better then expected? I wrote to Seagate who wrote that “As far as the sequential data rate goes, IronWolf 10TB is similar to that of the previous generation 8TB enterprise capacity HDD. Our new generation of IronWolf 10TB HDD increased areal density mainly from increased track density with helium technology. Given the same amount of data written on the drive, 10TB drive requires less seek compared to that of an 8TB HDD. This short stroking effect is an incremental performance boost. In addition to the performance gain from areal density increase, IronWolf 10TB benefited from caching algorithm tweaks on 256MB as part of the AgileArray. The net effect is a big performance gain for the end-user. In the same vein, our new 10TB enterprise capacity HDD is optimized for its intended application with similar performance gains over the previous product generation. Our main goal was to optimize IronWolf HDD for best user experience in a NAS application.  I hope we achieved that goal.”

From our tests, they met that goal and more. According to Seagate, additional improvements include: “Rotational vibration (RV) sensors to support consistent performance by reducing vibration in one-to-16-bay NAS systems. Expanded multi-user capabilities to deliver a user workload rate of 300TB per year – more than five times the rate of a standard desktop drive. AgileArray delivers drive balancing by using dual-plane balance and rotational vibration sensors, RAID optimization for increased performance and advanced power management.”

It was now time to start swapping out the original 4TB NAS HDD drives for the IronWolf 10TB units. One thing to keep in mind, that a 4 drive NAS, operating at RAID 5 has one drive for protection, and the moment you remove that drive, you better start praying that nothing goes wrong during the rebuilding process, and the larger the capacity difference the longer it takes. Since we were going from 4TB to 10TB per drive, that’s an enormous increase in capacity. I did some calculations on how long each drive would take to repopulate, and based on past experience I estimated around 12-16 hours per drive. As you will see, this was wildly optimistic, and way off the mark. It took much, much longer than I expected.

The actual time it took our system to synchronize 4 10TB drives from 4TB source drives on the Seagate NAS Pro was as follows:

Drive #1 – 20 Hours from start to finish

Drive #2 – 17 Hours from start to finish

Drive #3 – 28 Hours from start to finish

Drive #4 – 121 Hours from start to finish (5 Days)

Why the variation in times? To be honest I’m not really sure, but I was away from the system and travelling for much of the time, so not placing enormous strains on the system. But, rebuilding a RAID always takes time, and since the final drive was the safety drive, our guess was simply that it took longer then the rest. Since you can use the NAS during the rebuilding, as an end user you never notice any significant changes, but I was glad that the NAS had a backup during the process, our other NAS Pro, which was created as an offsite backup of the NAS. But, keep this in mind as you expand the capacity of your NAS, make sure to back up the data, even with an old fashioned JBOD approach.

We recently upgraded the network will all new Netgear Gigabit Ethernet switches from their well-regarded NETGEAR SOHO Ethernet Unmanaged Switch series, in our case three GS308 (8 ports) and one GS316 (16 ports) Gigabit Ethernet switches to insure that the network had parity and to rule out any issues that might arise out of using a variety of switches of different specifications. Once the NAS Pro was fully populated, the transfer rates over our newly upgraded Gigabit network were 89.2 MB/s Write / 107.9 MB/s Read.

We were impressed by the Seagate 10TB IronWolf NAS HDD drives, and they come highly recommended, and look forward to the just released Seagate 10TB IronWolf Pro NAS HDD drives. The IronWolf has a 3-year warranty, while the upcoming IronWolf Pro feature a 5 years warranty and the included Seagate Rescue Service. If you need to update and increase the capacity of your NAS we think you should strongly consider the new IronWolf series.

Harris Fogel, posted 11/23/2016

For more information about the Seagate IronWolf Hard Drive series, visit:

For more information about the NETGEAR SOHO Ethernet Switch Series visit:

For more information on SoftRAID 5 visit: