Unscrupulous DM-SMR Shenanigans

At the end of last year i put together a Synology NAS containing Western Digital Red (NAS) drives. My goal was to pull all of the data scattered across multiple aging machines and external drives into one place. All of that worked out just fine.

Earlier this year a “scandal” broke where WD was found to have started shipping DM-SMR drives in part of a lineup where CMR was expected. In most cases this would be invisible to the user. However, in use cases such as NAS, certain operations would degenerate and become stupidly slow.

The original table showed that drives smaller than 8TB were now being shipped as SMR:

Not good – my new drives were 4TB – right in the middle of the bad range. An additional table showed the SKUs of drives which were effected:

Hmm. That is not the SKU that appears on my invoice. The parts supplied are WD40EFRX, perhaps i got lucky? Having pulled the drives from the NAS to check, it seems that i did indeed get lucky! There is a good write-up and extensive benchmark on Serve The Home which compares the performance of WD40EFAX and WD40EFRX labelled drives. Wasn’t looking forward to fighting the good fight with WD over having being mis-sold.

And, that is the point here – for most cases the performance of SMR and CMR drives is indistinguishable, it’s only when you go to rebuild a array, swap out a bad drive, create a hot spare, etc. that you start to have issues. For drives that are explicitly sold for use in NAS this is an unacceptable ‘bait-and-switch’.

It seems likely that WD will be forced to replace the drives that were mis-sold, but the amount of time and effort they have put into playing down their deception is likely to cost them a lot more in the long run.