WD Red drives spec'd for 1-8 bays - why?

[CountryBumkin]

I have a home Server setup with 15 hot swap bays (and two hardware RAID controllers).

I just put six (6) 3TB WD Red NAS drives in and six (6) 3TB HGST Deskstar 7K3000 drives in (on different controllers). Later I plan to add the remainder of drives (3) the case will hold as needed.

But the WD Red drives are spec'd for 1-8 drive bay systems - (HGST doesn't spec the number of bays - they just same for use in "desktop systems") so what is the issue with putting the WD drives in a larger system?

Does WD assume my 15 bay enclosure will run too hot?
They don't know what cooling fans/equipment I'm using.

Maybe its the amount of vibration generated with more than 8 drives spinning.

Does any one know what the concern is? Should I be concerned about the WD drive longevity?

 

[dave_the_nerd]

I would assume it's RAID tuning. Bigger arrays mean slightly different behavior for best performance, error recovery, reliability, etc.

In real life, they're going to be fine 99.9% of the time, in 99.9% of circumstances, but WD wants to scare you into buying more expensive drives.

And you probably wouldn't want to load ~90 of them into some nutso high density enclosure.

 

[CountryBumkin]

I would assume it's RAID tuning. Bigger arrays mean slightly different behavior for best performance, error recovery, reliability, etc.

In real life, they're going to be fine 99.9% of the time, in 99.9% of circumstances, but WD wants to scare you into buying more expensive drives.

And you probably wouldn't want to load ~90 of them into some nutso high density enclosure.

Good answer. Thanks.

In my case I will have 8 drives on one controller (a 3Ware 9650SE-8LP) and 7 drives on the other. So, I guess I won't be violating WD's max 8-bay rule/recommendation.

 

[Fallen Kell]

Actually the issue is vibration control. All the disks in a RAID array will tend to be performing the same seek operation at the same time, amplifying the vibrations generated from each individual disk. At some point those vibrations will result in the drive attempting to operate in conditions outside of its tolerance for external vibrations, resulting in the control arm being pushed far enough away due to the vibration that it is no longer aligned with the proper track on the disk, resulting in failed reads/writes or worse, corrupting the data on the next track over from the one that it thought it was on (or reading the data from that adjacent track).

WD is simply rating the disks to be good when using up to 8 drives at once in any kind of array. Obviously having enclosures that dampen the vibrations will allow more disks to be used. If you want more information on this, BackBlaze has extensive information covering this available in their articles about how they designed their storage pod (like aligning the disks in pairs bottom to bottom such that their rotational spins cancel out forces of the other disk, and how they suspend the disks using "bungee"cords to prevent from transferring vibrations to other disks, etc., etc.,)

 

[CountryBumkin]

Thanks for clarifying that.

My case is using three Supermicro hot swap 5-bay enclosures/backplanes in a huge Lian-Li tower case which is very well build and insulated. And I'm only running 8-drives on the same controller, so unless I'm moving data from one controller (array) to the other, the two controllers won't be running at the same time - meaning all 12 drives won't be spinning at the same time. This should keep vibrations within WD tolerances/specs (most of the time).

If suppose if I start seeing drive failures in the future - I'll know why.

 

[It's Not Lupus]

They were originally specified for up to 5 bays. Then around the time the Red Pros came out, the marketing was changed to up to 8 bays.