"Pre-crash" question about replacement HDD

[guermantes]

Hi,
My 6 x 4 TB WD RED in a RAIDZ2 configuration is approaching five years spinning time and so far so good, no visible SMART errors, but I know the day is approaching when it ultimately will happen and I will need to replace some drives. So I thought I would straighten my question marks out now, to be able to quickly buy new drives when the day comes. It's a non-mission critical home box and my strategy is to bet on longevity so as to hopefully getting lower prices when the time comes (supply chain problems be damned).

From what I understand:

• I can mix brands, but the drive needs to be CMR
• I think I read somewhere that it is best to not mix RPM
• (I am aware I will not get more available space unless I change all six drives.)

But should I match other criteria to my current drives as well? Cache?

 

[winnielinnie]

In hindsight, hopefully you let TrueNAS create a "swap partition" on all the drives by default. This gives you the peace of mind that the next "4TB" drive you purchase will not be ever-so-slightly-smaller than your existing vdev members.

 

[Etorix]

From what I understand:

• I can mix brands, but the drive needs to be CMR

Yes. Basically, shop around for NAS or Enterprise drives and pick the best price per TB.

• I think I read somewhere that it is best to not mix RPM

Depending on how your drives are mounted and whether vibrations could propagate.
Anyway all newer NAS-capable drives are 7200 rpm.

But should I match other criteria to my current drives as well? Cache?

No.

 

[guermantes]

In hindsight, hopefully you let TrueNAS create a "swap partition" on all the drives by default. This gives you the peace of mind that the next "4TB" drive you purchase will not be ever-so-slightly-smaller than your existing vdev members.

Swap? As in "don't fill the pool to more than 80%" ? If so, yes I did.

Yes. Basically, shop around for NAS or Enterprise drives and pick the best price per TB.

Depending on how your drives are mounted and whether vibrations could propagate.
Anyway all newer NAS-capable drives are 7200 rpm.

No.

Great!
(Though, the WD RED Plus (post SMR scandal) is still 5400)

 

[winnielinnie]

Swap? As in "don't fill the pool to more than 80%" ? If so, yes I did.

No, as in the swap partition (which is by default 2 GiB).

Type in these commands to find out:

Code:

swapinfo -g

Code:

geom part list

Look for "type: freebsd-swap"

 

[Etorix]

(Though, the WD RED Plus (post SMR scandal) is still 5400)

No, these spin at 7200 rpm but are marketed as "5400 rpm-class"—whatever that means.

 

[guermantes]

No, as in the swap partition (which is by default 2 GiB).

Type in these commands to find out:

Code:

swapinfo -g

Code:

geom part list

Look for "type: freebsd-swap"

Thanks! Both commands inform me that I do have swap enabled. Must have been recommended in the wizard or automatically applied when installing.

No, these spin at 7200 rpm but are marketed as "5400 rpm-class"—whatever that means.

Wow, that's sneaky of them. That and the don't-say-we-switched-to-SMR débacle tempts me to buy Ironwolfs or similar just by protest. Thanks for the info!

 

[WI_Hedgehog]

You can mix RPM, NAS-grade drives have low vibration so it doesn't matter in that regard (consumer-grade drives can experience problems depending on the number of drives).

Realize though that 5,400 RPM drives tend to use less power, generate less heat/noise, and be "a little slower"--than 7,200 RPM drives of the same era, meaning new 5,400 RPM drives will generally out-run 10 or 15 year old 7,200 RPM drives by a wide margin. As an example, my 5-year-old HGST 7,200 RPM 6 TB drives will ~smoke~ my 12-year-old HP 10K RPM 320 GB drives, and eek out some performance over my not-quite-as-old HP 10.5K RPM 320 GB drives.

It therefore comes down to goals...if you have 1-year-old 3TB 5,400 RPM drives in the same vdev as 1-year-old 3TB 7,200 RPM drives the speed advantage of the 7,200 RPM drives will be lost, however they're still burning relatively more power than the 5,400 RPM drives. But say you have 5-year-old 7,200 RPM 3TB drives in vdevA and 1-year-old 6TB 5,400 RPM drives in vdevB and you combine them in pool1, things may "pretty much balance out."

ASIDE FOR THE GENERAL READER (not this use-case): If things are "off" you could add more drives to the faster pool and-depending on the layout-it might slow down (or instead add/remove a parity drive), or stripe more drives in the slower pool...it depends on your unique setup and usage, but I think that's getting a bit finicky on particulars and in general "close counts" unless we're talking tiny-datacenter volumes of drives and you're spinning 45+ drives, then taking a closer look might be worth your time.

Back on topic, we're talking (6) 4 TB WD RED in a RAIDZ2 configuration running continually for 5 years, meaning you are [statistically] somewhat lucky all of them are still running. Here's something to think of...buy 1 or 2 used drives off eBay and if one dies, throw in a backup. Mind you, drives tend to die in small groups...

 

[guermantes]

Energy and sound... didn't think about that. I think that's actually more important to me.
Let's hope Ironwolfs are true 5400 rpm, then. The "previous" model was apparently 5900