Hot Spare Confusion

[Evan Shaw]

I am currently in the process of setting up my new NAS, and I want to implement a hot spare that automatically rebuilds my RAID array (4x3tb RAID 10) when a disk fails. If I understand correctly, FreeNAS doesn't do this? Apparently you have to manually tell the hot spare to kick in, and the hot spare is constantly spinning, even while not in use. If this is true, is there any way to spin it down until it is needed? The forum threads I read were several years old and I just want to clear up some confusion.

 

[Mirfster]

As far as I know the Spare should kick in automatically. I can try to test this out later if needed; unless someone else already knows 100%. By chance what threads are you referring to? Can you post links to them?

 

[Evan Shaw]

https://forums.freenas.org/index.php?threads/why-hot-spare-doesnt-work.17287/

This was posted two years ago so I don't know.
Anyway, if they do work, do they constantly spin? I want an automatic hot spare that is dormant until another drive fails.

 

[dlavigne]

Older versions of FreeNAS did not, but FreeNAS has supported automatic hot spare for some time now (prob the last year or so).

 

[Evan Shaw]

Ok, thank you so much. Is the drive still spinning constantly though?

 

[Mirfster]

Ok, thank you so much. Is the drive still spinning constantly though?

Probably to some degree, but that should not be too much of a concern if you are using quality drives...

 

[Evan Shaw]

UPDATE: A spare does spin down even when the pool is accessed if you turn on disk standby per Storage -> View Disks -> Edit -> HDD Standby.

 

[SweetAndLow]

I'll point out that hot spares don't really make sense unless you don't have access to your system for long periods of time. If you can replace a drive in a day or 2 you might as well just use it in your system and get the added storage or protection.

Sent from my Nexus 5X using Tapatalk

 

[fta]

I'll point out that hot spares don't really make sense unless you don't have access to your system for long periods of time. If you can replace a drive in a day or 2 you might as well just use it in your system and get the added storage or protection.

There are other reasons to use spares. For example: you have a pool of mirrors, and you don't have hot swap drives. It's common for drives to fail on power cycle. It's safer to have the replacement already installed so a drive replacement doesn't require a power cycle.