Introduction

Seagate is one the most well-known names in the storage industry, and their hard drives are used by hundreds of millions of people around the world. Together with Western Digital, Seagate basically owns the market for mechanical hard drives, but that market is under attack from flash-based SSDs. SSDs achieve faster transfer rates and lower access times than hard drives because of their solid-state nature without any moving parts. On the other hand, the price per GB for SSDs is higher than HDDs, but prices have been steadily coming down over the years, which is now driving more and more budget-minded people into exploring what SSDs can offer over mechanical drives.

Without saying, this not only goes for desktop PCs, but also NAS storage systems, which is why Seagate is the world's first company to release an SSD optimized for NAS usage. Mechanical HDDs optimized for NAS have gained a significant market share in recent years, and pretty much every HDD vendor has released models for that scenario, so I can see the reason why customers and manufacturers would want to extend this support to SSDs, too.

Of course, the requirements are different because SSDs have no moving parts that could be made of higher quality. Another argument for NAS HDDs is that they are more resistant to vibrations from neighboring drives, which is not an issue with SSDs, either. What does matter for SSDs is performance consistency. With the introduction of TLC-based SSDs, which store three bits per cell for higher capacity and lower cost, write speeds have gone down significantly as writing to TLC is a lot slower than writing to SLC or MLC. The industry invented pseudo-SLC caching to mitigate that effect, which operates a portion of the TLC in SLC mode to soak up fast write bursts. However, the SLC cache size is limited, which leads to many TLC-based SSDs falling into the "TLC write hole" once their SLC cache is full and the drive has to write to TLC directly. Drops from 500 MB/s to 100 MB/s writes within a few seconds are quite noticeable and could lead to even more problems for multi-user NAS systems where you are not aware of how much data other users are writing at the same time—we'll take a closer look at this in the review.



The Seagate IronWolf 110 SSD is built around a Seagate in-house controller marked as "500021768". The 64-layer 3D TLC BiCS3 flash chips are made by Toshiba, and four Micron DDR3 memory chips provide 512 MB of DRAM memory for the mapping tables. Seagate has released the IronWolf 110 NAS SSD in capacities of 240 GB ($80), 480 GB ($125), 960 GB ($250), 1.92 TB ($450), and 3.84 TB ($860), which is an amazing range of capacities. Endurance for our tested 480 GB version is set at 875 TBW, and the other models scale accordingly depending on capacity, up to 7 petabytes (!) total bytes written for the 3.84 TB version.

Warranty for all models is set at five years, with two years of data recovery services included. Basically, if you can no longer access your data due to data corruption, user error, or water and fire damage, Seagate will do their best to recover your files for free.