WD Red don't buy slow drives

[John Doe]

Hi Folks,

today a german news plattform published some insights about SMR, PMR or CMR technologies in Western Digital Hard discs.

For those non german speaking frieds:

Western Digital has admitted to using two different recording techniques, one of which is significantly slower, on the WD Reds intended for NAS systems without labeling. In a statement, the manufacturer now explains which models use which technique, because there were errors in raid networks with ZFS file system.


The WD Reds are offered with 2 TByte to 14 TByte capacity, whereby even the data sheet does not give any concrete information about the recording technology of the drives, but only about the transfer rates and the caches. Some users noticed after the installation of a hard disk drive that error messages appeared after one or two hours in a ZFS network and the affected HDD was removed from the raid.

The background is that the first batches of WD Red were shipped with Perpendicular Magnetic Recording (PMR) aka Conventional Magnetic Recording (CMR). In the meantime, however, there are also models on the market that use Shingled Magnetic Recording (SMR) - without marking. This type of recording with overlapping tracks allows a higher capacity, but reduces the writing speed significantly.

According to Western Digital, only the WD Red with 8 TByte to 14 TByte use the classic Perpendicular Magnetic Recording, the models with 2 TByte to 6 TByte however use the slower Shingled Magnetic Recording. A renewed look at the data sheet shows that the smaller HDDs with 64 MByte cache achieve a sequential transfer rate of 147 MByte/s to 150 MByte/s, whereas the larger hard disks with 256 MByte buffer achieve 196 MByte/s to 215 MByte/s. What falls under the table is the significantly lower transfer rate for random access. The slower SMR models are now (pdf) marked as EFAX, whereas the faster PMR drives are marked with EFRX .

Note from my end; it seems the article did a mistake I think the slower ones are actually EFRX, while the faster ones should have EFAX

Link to article:
Golem.de

Accoring to the comments this is valid for the drives after June 2019

how to check:

 

[cobrakiller58]

There is thread in off-topic about this WD thing going on right now.

 

[John Doe]

ah sorry, did not see that.

 

[G Brown]

SMR drives submarined int Red disk products,
fyi, more:
article: https://blocksandfiles.com/2020/04/14/wd-red-nas-drives-shingled-magnetic-recording/

#1313 (Beware of SMR drives in CMR clothing) – smartmontools

www.smartmontools.org

 

[cobrakiller58]

ah sorry, did not see that.

no reason to be sorry just thought you might want to jump in on it too.