mixing hard disc speeds

[barrydocks]

Need some advice about mixing hard drive speeds. Stupidly I built my PBS with 4x3TB Toshiba 7200 desktop drives (not sure what I was thinking) and after 12months one is failing.

I plan to swap them all out for Seagate 5400 NAS drives. The idea being to replace each drive and sync' the ZFS raid after each swap. This means that there will be a mix of drive speeds until all 4 are swapped, will this cause a problem?

 

[EllerholdAG]

No mixing drive speeds is fine. The pool will be as slow as the slowest drive though. But if you want to trade down, you already expect that.
AFAIK what you cant mix is 4k / 512 drives. So make sure your new drives have the same format as the old ones. So either 4k native, 512 emulated or 512 native.

If you want to switch out EVERY drive it is usually better to just create a new pool and use syncoid to migrate all of it. This way you only need to write everything once instead of everytime for every drive.

 

[barrydocks]

No mixing drive speeds is fine. The pool will be as slow as the slowest drive though. But if you want to trade down, you already expect that.
AFAIK what you cant mix is 4k / 512 drives. So make sure your new drives have the same format as the old ones. So either 4k native, 512 emulated or 512 native.

If you want to switch out EVERY drive it is usually better to just create a new pool and use syncoid to migrate all of it. This way you only need to write everything once instead of everytime for every drive.

Thanks for the reply. That's super helpful. I was thinking that the drop in speed wouldn't be an issue for a backuk up server, I have fast SSDs in my PVE server.

The other problem I have is that my box only has 4 drive bays, so adding another 4drives for a new pool is not an option, hence swapping out one drive at at time.