As we have previously explained, hard drives that use SMR technology have a higher data density per plate because tracks are written overlapping each other, which in turn allows the manufacturer save production costs. However, this causes a lower performance and if they are used in RAID systems they give parity problems when trying to do a restoration, causing data loss.
What technology does each WD hard drive use?
This is the list as published by the company:
Format | Capacity | WD Red | WD Red Pro | WD Blue | WD Black | WD Purple |
---|---|---|---|---|---|---|
3.5 " | 1TB or less | CMR | CMR | CMR | CMR | CMR |
3.5 " | 2TB – 6TB | SMR | CMR | SMR / CMR | CMR | CMR |
3.5 " | 8TB or more | CMR | CMR | – | – | CMR |
2.5 " | 500GB or less | – | – | CMR | CMR | – |
2.5 " | 1TB | CMR | – | SMR | SMR | – |
2.5 " | 2TB | – | – | SMR | – | – |
So, now we know that it is not only the WD Red drives that have SMR technology, but there are also many WD Blue and even the 2.5 TB 1TB WD Black are also SMR drives.
If you have an SMR disk you must let it "rest"
As WD has posted on its blog, its WD Red hard drives are designed for home users and SMBs, especially for NAS with 1 to 8 bays, and deliver excellent performance that has been tested and corroborated by numerous NAS manufacturers. These disks (be they SMR or CMR) are prepared for workloads of up to 180TB per year and they indicate so in their technical specifications.
The fact is that due to how SMR technology works, the data is written to free sectors of the disk and later, when the disk is at rest, the DMSMR is dedicated to putting the data in its place. According to the manufacturer, if we overload the disk and don't give the DMSMR time to do its job, that's when the performance dips occur, but they say this is the user's fault because they will be using the disk above their specification.
Definitely: WD has tricked users selling slower SMR discs and giving problems without warning, and making more profit with it. When they have been discovered they have published the complete list when they are under pressure, but saying that the discs are designed in a certain way and that it is the fault of the user when they give problems because they do not use them properly. And finally, urging users (of course) to buy better and more expensive records.
For all these reasons, at this time we can only recommend that you do not buy WD hard drives until the company is not responsible for their actions and acts in favor of the users and not in their own interests.