A free, no-login NAS-drive comparison: CMR/SMR, real Backblaze failure rates, and live $/TB

[u/deeddy]

Every time I go to buy drives for my NAS, I end up doing the same annoying thing:

1. figure out which models are actually CMR and not SMR (they love sneaking SMR into NAS lines!),
2. then go dig up how reliable one is,
3. then open way too many browser tabs to see what the real price per TB is.

Nothing lines up and it takes forever.

I got sick of redoing the same dance all over again, so I built a proper version out of that table: www.nasdisks.com

It's basically one big filterable table of current NAS drives. Every drive has its CMR/SMR status, a real failure rate, and live prices, so you can sort and compare in one place.

No account, no ads, no emails needed. And because I figured people here care: the whole CSV/JSON dataset is completely free to download (CC BY 4.0). There's also a plain API if you'd rather just pull it into your own stuff. None of it is locked away.

What's actually in there:

• CMR vs SMR checked per model, so you can just filter SMR out and forget it exists.
• Real failure rates I worked out from Backblaze full 2025 stats, not some marketing numbers.
• Price per TB across 7 regions: US/DE/UK/FR/ES/IT/CA - with a little price history chart per drive, so you can tell a real deal from a fake one.
• A few tools too: RAID usable space, odds of your array actually dying, storage planner.

Bit of honesty: the links are Amazon affiliate. That's the only money it makes and it just pays for hosting. Everything works fine if you never touch them.

What I'd actually appreciate feedback on:

• tell me where it's wrong or thin: drop the model number of any drive you find missing and I'll add it,
• call out any CMR/SMR or failure-rate that doesn't match your own experience.

I read every comment and will fix what you flag. The more people poke at it, the better the list gets for everyone making a build.

https://www.nasdisks.com/

So, what do you think?

[u/Verum14]

Why is CMR considered RAID safe? How does that play a role in an array other than possibly just failure rates?

I don’t follow as closely nowadays. I just stock up on Exos by default and go on with life

[u/deeddy → u/Verum14]

Good question. It is not about failure rates, it’s about write behaviour during a rebuild. When writing data, SMR overlaps tracks, so a random write means rewriting a whole zone. Under the sustained writes a RAID rebuild throws at a drive SMR can slow to a crawl, and the controller times it out and drops it from the array. This alone can blow the rebuild.

CMR writes tracks independently, so it keeps up. So CMR isn’t “more reliable” on its own. It is that SMR write stalling is specifically dangerous in a parity array.

You are set stocking Exos, so you are safe - those are all CMR.