Selecting a HDD for (a kind of) NAS


Occasional Visitor
Hi !

I already have a Raspberry Pi 4 with a bunch of external USB drives to it, and it's somehow... fine. With one disk I got about 80 MB/s read and write, and other three (same model) 35 read and 64 MB/s write. They are quite old... and they are all SMR. So I thought of buying some new hard disks... I don't want to make a real NAS, I just want to connect some drives to the Raspberry Pi, that's all. No RAID, no other special functions... I decided to go with Seagate... because those from Western Digital don't offer any technical specifications about their drives, they only give us the physical dimensions as if we were fools who don't need to know anything.

So I did a little research on Seagate 4TB hard drives (I need 2 of these):
(red is bad, green is good, and orange is intermediate)

For me, the most important aspects are:
- Type CMR or SMR
- Consumption
- Noise
- Start time

So from what can be seen the Pro versions (Firecuda and Ironwolf) have the most bad points. Then the Baracuda is out of the game just because it's SMR (otherwise it's pretty good).

The final battle is between Ironwolf and Skyhawk:
- Both have the same noise level
- Ironwolf consumes a little more, but almost insignificantly
- Instead, Skyhawk starts almost 2 times faster (very important!)

For me, the operating mode of the hard drive is as follows:
- it will be powered non-stop
- it will have to enter stand-by after 20 minutes of idle time (preferably by default)
- because it will always enter stand-by, it matters a lot how quickly it can switch back to operating mode
- it will be used quite rarely (perhaps a maximum of 1 hour/day and not every day)
- will be accessed by only one user (me)
- it should be as silent as possible
- I don't want any special function (RAID, etc...), I just want a simple HDD

Which do you think would be more suitable between the 2 ?

I would like Skyhawk better because it starts the fastest and is also cheaper than Ironwolf. But I don't understand what the difference between them is supposed to be. Ironwolf is said to be for NAS and Skyhawk for surveillance cameras... OK. I don't know how it could be a special HDD for surveillance cameras... An HDD is a storage medium, that's all. What does it matter what you put on it? Both are made to work 24/7... So I really don't know what makes them so different. If it is for surveillance and I copy some movies on it, what will happen ? It will die ? :))

What amazes me the most is the start-up time of these hard drives... How can they start in 17...23 seconds? Well, the ones I have now stacked in the hub and connected to the Pi start in about 4 seconds... 2TB (2.5") external HDDs. How can you wait 23 seconds to be able to access your disk ? :(

Tech Junky

Very Senior Member
Nas - cmr
Surveillance - smr

Seagate is my last choice but, the exos line would be my choice.

WD Red is what I'm running and 8tb and higher don't have to worry about smr.


Occasional Visitor
I found the specs for WD drives too (my bad)...
I seems that WD Red Plus is a pretty cool HDD, but I can't find the start time (ready time). If it were comparable to the Skyhawk, I would buy it right away !
Can any of you, who have it, tell me how long it takes to wake up from sleep... It's a popular model, I think many people have it.
I mean, for the WD Red Plus 4TB (WD40EFPX).



Part of the Furniture
For what it is worth I stopped using Seagate drives several years ago. I was having just too many failures on almost new as well as mid age drives. I have some WD drives that are 10 tears old and still working. I do have a NAS with two WD Red CMR 4 TB drives. The NAS gave me a warning on one of the the drives a few months ago and I replaced it with a WD40EFZX, a Red Plus with 128 MB Cache. The so called "failing" drive has been tested with Gsmartcontrol and now passes the tests and shows no errors.

As for spin up time I do not know. The drives in the NAS do sleep and it seems the device is ready when it is needed.

Tech Junky

Very Senior Member
For all intents and purposes here.... 2 drives @ ~5W is only 10W which is less than an LED lightbulb for consumption. just leave them running and reduce the wear/tear on them over the long term use. Considering you're planning on putting them into a low power system per your PI thread the overall cost to run this 24/7 should be ~$5/YR or less.


Occasional Visitor
From my calculations (where I live), it is about 22$/year. :)
Do you think they wear out more if they start and stop several times a day, than if they stay on all the time ?

Tech Junky

Very Senior Member

The load cycles are what you're dealing with when using APM.

$22/yr by your calculations is cheaper than replacing one before 5 years is up or 3 years depending on the drive you go with for the warranty period.


Very Senior Member
From my calculations (where I live), it is about 22$/year. :)
Do you think they wear out more if they start and stop several times a day, than if they stay on all the time ?
Yes. I've seen drives only fail when the stopped spinning and never turned back on. I actually disable all sleep on my drives and let them run if the unit is on.

And if you want quiet, it's the desktop drives you want. But they are also the least reliable. The most reliable drives will be close to enterprise designs which are the loudest.


Very Senior Member
I am running 2 of the 4TB Skyhawk drives in my Plex server. They are setup as a mirrored set. No complaints so far.

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