Re: Replacing a REMOVED drive in DEGRADED zpool

On 21/08/2025 01:55, Robert wrote:
> I have my first zpool degraded on a FreeBSD 13.5 server and looking 
> for advice on the steps I'll be taking to successfully replace the 
> REMOVED drive in a 4 disk 2 mirror zpool. It is scrubbed monthly with 
> last scrub August 3rd...
>
Funnily enough I wrote about this exact thing in Feb:

https://blog.frankleonhardt.com/2025/freebsd-zfs-raidz-failed-disk-replacement/

Okay, you're configuration is mirrors but I think most of the same 
applies. Note what I say about making the replacement disk bootable, 
which doesn't seem to have been mentioned in this tread.

Also, posted a script on this list that installed ZFS manually and other 
stuff a few months later. Guess what got me interested :-)

Since then I've had a spectacular failure of a ZFS mirror that had been 
happy for years. The problem with mirrored drives is that when you 
replace one it thrashes the other while it's resilvering, so if the old 
one becoming dodgy it could push it over the edge. I hope you have more 
luck than I did.