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WD Red Hard Disks: CMR vs SMR

ukbobboy01
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WD Red Hard Disks: CMR vs SMR

Dear Forum Members, especially StephenB

 

It's been a time since I've visited the hallowed pages of this forum and, as expected, time as moved on and new HD technologies have been introduced.

 

I'm planning to buy a couple of WD Red HDs in the near future but I see now, since the last time I bought WD Reds, a new technology has been introduced, i.e. SMR, but the older CMR tech is still being used and in fact still recommended by some WD Red users.

 

However, as a ReadyNAS user I would like to know what forum members think about the Red drives with SMR, as opposed to the Red drives still using CMR.

 

Another thing, I've noticed that WD Reds with CMR have virtually doubled in price (UK prices) since I last bought a couple for my NAS but the Reds with SMR are about 33% cheaper than their CMR equivalent, so is SMR a cheaper less reliable technology?

 

I eagerly await forum members opinions.

 

UK Bob

Model: RND2000v2|ReadyNAS Duo v2 Chassis only
Message 1 of 7

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StephenB
Guru

Re: WD Red Hard Disks: CMR vs SMR


@ukbobboy01 wrote:

PS. Is it true that there's a consumer class action against WD for the way they introduced SMR into the HD market?


Yes (in the US and Canada). 

 


@ukbobboy01 wrote:

 

For myself, I'm worried about compatibility issues, e.g. will these SMR drives work with my current CMR ones or even work with my old ReadyNAS's OS (probably not). 

 


I think the system will accept them, but that the performance will be worse than with CMR drives.  How much worse is hard to say.  You can read through the arstechnical tests earlier, they are probably closer to what you'll see in legacy ReadyNAS than the servethehome tests.

 

One option would be to go with jbod (one volume per disk), and not use RAID.

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Message 6 of 7

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StephenB
Guru

Re: WD Red Hard Disks: CMR vs SMR

Here is one set of tests with the ZFS file system:

To be fair, there are some other testers that didn't see such poor results, but they still found that the WD Red SMR drives didn't perform as well as CMR drives.

IMO, SMR is not a good option for ReadyNAS OS-6 systems using RAID.  Some users here have seen excessive resync times with them.  I've avoided them (and purchased WD Red Plus drives recently, which are CMR).

Message 2 of 7
Sandshark
Sensei

Re: WD Red Hard Disks: CMR vs SMR

Replacing a single 6TB CMR Red drive with an SMR (before WD's sneaky substitution became common knowledge) in a 6-drive RAID5 more than tripled the time it took my ReadyNAS to perform a scrub and totally locked up everything else while it was happening.  Had I not gone to SSH and canceled the scrub, allowed other stacked up processes to complete, and then resumed the scrub, it may never have completed.

 

Replacing that drive with an 8TB (still CMR) Red eliminated the problem, confirming it was the SMR drive that caused the issue.

 

My conclusion is that SMR drives have no business in any RAID system and WD should be taken to court for selling those pieces of junk as acceptable for that use.

Message 3 of 7
StephenB
Guru

Re: WD Red Hard Disks: CMR vs SMR


@Sandshark wrote:

WD should be taken to court for selling those pieces of junk as acceptable for that use.


They have been.  https://www.tomshardware.com/news/wd-class-action-lawsuit-smr-hard-drive-us-canada

Message 4 of 7
ukbobboy01
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Re: WD Red Hard Disks: CMR vs SMR

Hi Stephen

 

Thank you for your quick reply, especially as It's been such a long time since I've been here.

 

As it happens, I was watching a YouTube video about the differences between SMR and CMR Red drives and how WD are trying to sneakily sell them to customers without making them aware of the pit falls.

 

For myself, I'm worried about compatibility issues, e.g. will these SMR drives work with my current CMR ones or even work with my old ReadyNAS's OS (probably not). 

 

TBH, my problem is that I have recently bought an unused ReadyNAS Duo v2 on eBay, the original user bought but never actually used it, he decided to go with Synology instead.  Since I have a couple of RNDuo v2's already, and I'm familiar with this device, I jumped at the chance to get another one. And once I can verify it is in good working condition, I intend to populate it with WD Reds.

 

But I now see that WD Reds are not just the Reds I bought a few years ago, an unfavourable variant has now been introduced that should be avoided at all cost.

 

Finally, does anyone know why WD is trying to introduce SMR drives in such a sneaky way and so trash it's reputation that it has built up over the years?

 

UK Bob

 

PS. Is it true that there's a consumer class action against WD for the way they introduced SMR into the HD market?

Model: RND2000v2 (ReadyNAS Duo v2)|READYNAS DUO v2 (DISKLESS)|EOL
Message 5 of 7
StephenB
Guru

Re: WD Red Hard Disks: CMR vs SMR


@ukbobboy01 wrote:

PS. Is it true that there's a consumer class action against WD for the way they introduced SMR into the HD market?


Yes (in the US and Canada). 

 


@ukbobboy01 wrote:

 

For myself, I'm worried about compatibility issues, e.g. will these SMR drives work with my current CMR ones or even work with my old ReadyNAS's OS (probably not). 

 


I think the system will accept them, but that the performance will be worse than with CMR drives.  How much worse is hard to say.  You can read through the arstechnical tests earlier, they are probably closer to what you'll see in legacy ReadyNAS than the servethehome tests.

 

One option would be to go with jbod (one volume per disk), and not use RAID.

Message 6 of 7
ukbobboy01
Star

Re: WD Red Hard Disks: CMR vs SMR

Hi Stephen and Sandshark

 

Thanks for your input to this discussion, which has help me to make up my mind towards future HD purchases.

 

It now seems the best way to go is to purchase WD Red Plus in the future, the prices of the Red Plus drives are still within the bounds of being affordable and as long as they maintain their reliability I will continue to buy them as and when needed.

 

So my next planned purchase will be 2 x 3TB WD Red Plus HDs, hopefully in the new year.

 

Thanks for your help and advice.

 

And guys, have a merry Christmas and a happy (better than 2020) new year.

 

UK Bob

Model: RND2000v2|ReadyNAS Duo v2 Chassis only
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