Seagate is one of the largest manufacturers of hard disk drives (HDDs) in the world. In recent years, Seagate has begun producing drives using shingled magnetic recording (SMR) technology in some of their drive lines. SMR allows for greater storage density but can impact performance in some workloads.
What is SMR?
SMR is a hard drive recording technology that was introduced in 2011. In SMR drives, the tracks on the platters are partially overlapped or “shingled” which allows for higher track density. This increases overall storage capacity. However, this overlapping design also comes with some tradeoffs compared to conventional perpendicular magnetic recording (PMR) drives.
The main challenges with SMR are:
- Rewrites are slower – To rewrite data on an SMR drive, extra work is required to read/modify/write the overlapped tracks.
- More cache is required – The drive needs more cache and algorithm optimization to help manage the complexity of reads and writes.
- Not ideal for some write-intensive workloads – SMR can exhibit slower write speeds in workloads that are write-intensive, have random writes, or sustained write throughput.
SMR drives are better suited for write-once, read-many type workloads like archival data and cold storage. The increased density makes SMR a cost-effective solution for those use cases. For active workloads with more rewrites, PMR remains the preferred choice.
Does Seagate use SMR technology?
Yes, Seagate has been shipping select drive models that utilize SMR technology since 2013:
- In 2013, Seagate introduced the 1.5TB Laptop SSHD which used SMR in combination with NAND flash memory.
- In 2015, Seagate announced several SMR-based Archive HDDs with up to 8TB capacities.
- In 2016, they released 10TB drives for networked attached storage using SMR.
More recently in 2019-2020, Seagate has been transitioning some of their high capacity desktop HDDs to SMR technology:
- The 8TB, 10TB, 12TB, 14TB and 16TB BarraCuda Pro drives switched to SMR circa 2019.
- The high capacity 2.5″ BarraCuda and Mobile HDD models also moved to SMR in 2019-2020.
- The latest 18TB Exos X18 (and prior 16TB/14TB models) data center drives use SMR technology as well.
So in summary, Seagate uses SMR technology across portions of their product portfolio spanning laptop drives, consumer NAS drives, data center drives, and backup/archive models. However, many of Seagate’s drives still use conventional PMR recording as well.
Seagate’s SMR Drive Models
Here is a more detailed look at the Seagate drive lines and capacities that leverage SMR technology as of 2021:
Laptop HDDs with SMR
- Laptop HDDs: Some Seagate 500GB, 1TB, and 2TB 2.5″ laptop drives use SMR, while others remain PMR.
- Laptop Thin HDDs: The 500GB, 1TB, and 2TB Thin drives utilize SMR technology.
- Laptop SSHDs: Seagate’s 1TB and 2TB hybrid Laptop SSHDs with NAND flash use SMR recording.
Desktop HDDs with SMR
- BarraCuda drives: Select BarraCuda models have transitioned to SMR including 8TB, 10TB, 12TB, and 14TB capacities.
- BarraCuda Pro drives: The 8TB, 10TB, 12TB, 14TB, and 16TB BarraCuda Pro now use SMR technology.
- SkyHawk drives: Seagate’s SkyHawk consumer NAS hard drives are SMR for models 8TB and above.
Enterprise HDDs with SMR
- Exos X drives: Seagate’s highest capacity Exos X enterprise drives use SMR including 16TB, 18TB models.
- Archive HDDs: The Archive HDD v2 is SMR for all models from 4TB to 16TB capacities.
Here is a table summarizing some of Seagate’s popular drives and which models utilize shingled magnetic recording vs perpendicular magnetic recording:
|Seagate Drive Line
|SMR or PMR?
|BarraCuda 2.5″ 500GB-2TB
|Mix of SMR and PMR
|BarraCuda 3.5″ 1TB-6TB
|BarraCuda 3.5″ 8TB-16TB
|BarraCuda Pro 1TB-6TB
|BarraCuda Pro 8TB-16TB
|IronWolf Pro 1TB-20TB
|Exos X16 16TB-18TB
Identifying Seagate SMR Drives
Since Seagate does not always specify recording technology used, how can you identify if a Seagate drive uses shingled magnetic recording? Here are some tips:
- Run the serial number through Seagate’s warranty checker. Their database will indicate if a drive uses SMR.
- Check the model number. Seagate model numbers that end in DM indicate SMR (e.g. ST4000DM004).
- High capacity drives above 6TB for desktop or above 10TB for data center are likely SMR.
- SMR drives will perform differently in benchmarks, with slower rewrites.
Seagate does not make the use of SMR easily identifiable for consumers. Your best bet is to research the specific drive model to determine if SMR is used. Seagate also does not tend to disclose if a model has transitioned from PMR to SMR during its lifecycle.
Performance Impact of SMR
How does using shingled magnetic recording impact performance compared to standard PMR hard drives? Here is a high-level look at the pros and cons:
Pros of SMR for Seagate drives:
- Higher maximum drive capacities. For example, Seagate SMR makes possible their 16TB desktop and 18TB enterprise drives.
- Lower cost per TB for high capacity drives. SMR allows Seagate to offer more dense drives at lower costs.
- Faster sequential write speeds in ideal scenarios. SMR writes new bands sequentially at high speed.
Cons of SMR for Seagate drives:
- Slower random write performance. Random writes require rewriting shingled tracks.
- Slower rewrite speeds under workloads that overwrite existing data.
- Not ideal for RAID. SMR drives can cause long rebuild times for RAID due to lower rewrite speeds.
- Heavily impacted by caching/queue depth. SMR performance depends heavily on drive caching strategies.
In general, SMR provides higher capacities but reduced performance compared to traditional PMR hard drives. The impact depends heavily on the workload. For mostly sequential writes or cold storage use cases, an SMR Seagate drive can perform well. But for active use cases involving lots of rewrites, PMR is likely the better choice.
Benchmarks of Seagate SMR Drives
Looking at benchmarks helps illustrate the performance differences between Seagate’s SMR drives and standard PMR hard drives. Here are results from some benchmark tests on popular Seagate models:
Seagate BarraCuda 8TB SMR vs PMR
- PMR BarraCuda 8TB – 163 MB/s sequential reads, 158 MB/s sequential writes
- SMR BarraCuda 8TB – 195 MB/s sequential reads, 168 MB/s sequential writes
- The SMR 8TB drive shows faster peak sequential speeds, but…
- PMR model sustains write speeds better under mixed workloads
- SMR drive write speed drops to 75 MB/s during drive fill benchmark
Seagate Exos 16TB SMR vs 14TB PMR
- PMR Exos 14TB – 252 MB/s sequential reads, 197 MB/s sustained writes
- SMR Exos 16TB – 260 MB/s sequential reads, 245 MB/s sequential writes
- The Exos 16TB SMR drive shows faster peak write speed due to SMR sequential write behavior
- But the PMR 14TB model offers more consistent all around performance
Additional drive benchmarks likewise confirm the general performance profile of Seagate SMR drives:
- Strong peak sequential write throughput, but inability to sustain max speeds under mixed workloads
- Much lower performance during random overwrites due to rewriting shingled tracks
- Highly variable performance dependent on caching algorithms
- SMR impacts consistency and predictability of performance metrics
Using SMR Drives
Seagate’s SMR drives can deliver great capacities at low costs for the right use cases. But their performance limitations make them less suited for typical desktop usage. Here are some tips on the best uses for Seagate SMR drives vs configurations to avoid:
Recommended uses for Seagate SMR drives:
- Archival or backup data
- Media servers for video/music libraries
- Cold storage / infrequently accessed data
- Network-attached storage (NAS) for data that changes infrequently
Setups to avoid with Seagate SMR drives:
- OS or applications drives
- RAID arrays
- Frequently accessed or rewritten data
- Scratch disks for content creation
- Caching drives
- High performance computing
For home users, Seagate SMR drives are generally recommended only for dedicated media storage rather than as general desktop hard drives. For businesses using SMR, it is critical to tier data appropriately to avoid performance issues.
- Seagate uses shingled magnetic recording (SMR) technology in portions of their consumer, NAS, and enterprise drive portfolio.
- Higher capacity drives above 6TB for desktop and above 10TB for enterprise often utilize SMR.
- SMR provides higher capacities but reduced performance compared to traditional perpendicular magnetic recording (PMR).
- Seagate SMR drives can deliver good value for cold data use cases but are less suitable for active workloads.
- Check specific drive models carefully, as Seagate’s SMR use is not always clearly disclosed.
Seagate will likely continue transitioning models to shingled magnetic recording as they push drive capacities higher. This allows them to deliver more dense drives at low costs. But purchasers should be aware of the performance tradeoffs associated with SMR when choosing the right storage drive for their needs.