Using old and new WD NAS Drives in a RAID array

Forums › Desktop computing › Using old and new WD NAS Drives in a RAID array

JimmyH

2886 posts

Uber Geek

#260265 18-Nov-2019 13:35

I'm slightly out of my depth here, as I'm not really a server/hardware guy, and apologies if this isn't the correct forum.

I have a hardware RAID array, using WD Red NAS drives (WD60EFRX, which is a PMR drive). I have two free bays and am low on storage, so the obvious solution is to drop in another drive or two of the same size and expand the array, which I have done quite happly before. However, the WD60EFRX drive seems to be been superseeded, and the WD Reds on the market now (WD60EFAX) seem to be SMR drives.

I have read various comments, including official advice from Synology, that:

SMR drives don't work as well as PMR drives in RAID arrays. and
SMR and PMR drives should never be mixed in the same RAID array.

I'm a bit confused as to:

whether this is really an issue, or can I sleep safely after dropping EFAX SMR drives into the same array as EFRX PMR drives?
if this is an issue, is there any issue dropping a simlar sized NAS drive from another maker (say a 6TB Seagate Ironwolf drive which I understand will still be PMR) into the same array as the 6TB WD Drives?

Also, WD have been really sneaky about this, which annoys me. You seem to have to really dig to discover that the drive that was previously PMR is now SMR. They seem to be actively trying to conceal/muddy this for some apparent reason?

Dynamic

3866 posts

Uber Geek

ID Verified

Trusted

Lifetime subscriber

#2355741 18-Nov-2019 14:28

Think about your usage case.

If this is important data on an array that needs to perform, sticking with PMR would be your best bet. Mixing drive brands should not be an issue, and some even encourage it so you don't end up in a situation where you have a bad batch of drives in a RAID array and they all go toes up in rapid succession.

If you were going to add a pair of new drives into a basic NAS or similar and this is backup storage or holds a big media library or something like that, have these two drives as a separate chunk of storage (beside, but not part of the same RAID array), you should be fine adding SMR drives.

Note - I'm speaking from general experience with RAID over the years, and not specific experience with these drives.

“Don't believe anything you read on the net. Except this. Well, including this, I suppose.” Douglas Adams

Referral links to services I use, really like, and may be rewarded if you sign up:
PocketSmith for budgeting and personal finance management. A great Kiwi company.

JimmyH

2886 posts

Uber Geek

#2370941 9-Dec-2019 10:57

Dynamic:

Think about your usage case.

If this is important data on an array that needs to perform, sticking with PMR would be your best bet. Mixing drive brands should not be an issue, and some even encourage it so you don't end up in a situation where you have a bad batch of drives in a RAID array and they all go toes up in rapid succession.

If you were going to add a pair of new drives into a basic NAS or similar and this is backup storage or holds a big media library or something like that, have these two drives as a separate chunk of storage (beside, but not part of the same RAID array), you should be fine adding SMR drives.

Note - I'm speaking from general experience with RAID over the years, and not specific experience with these drives.

It's for my media server. I don't really want to create a separate storage pool as I want to add one drive for parity (moving the pool from RAID5 to RAID6) and the second for more space. It looks like I will go with Seagate Ironwolf drives of the same capacity.

However, I will do this reluctantly. I'm not a huge fan of Seagate (which is why I originally went with WD drives); due to appallingly high failure rates on Seagate external drives I experienced a few years ago.

JimmyH

2886 posts

Uber Geek

#2462068 15-Apr-2020 17:07

To close the loop, I have a bit of an update on this.

Western Digital appear to have finally come clean on this, after ducking the question since mid-2019. They are indeed shipping their new NAS drives based on SMR instead of CMR technology.

[url=] https://blocksandfiles.com/2020/04/14/wd-red-nas-drives-shingled-magnetic-recording/

As the article notes, this is a pretty poor option for RAID arrays. It's also pretty shabby of WD to duck and weave, and essentially deliberately mislead, customers on this.

It looks like it's Seagate drives for me (shudder) now. And soon, as I'm showing a drive failure on my main RAID array. I just hope server drives ship as essential items during the lockdown.

And it looks like avoiding WD Reds below 8TB is sound advice for anyone with a RAID array.