ZFS: rpool: replace with smaller disk?

[oguruma]

I have my install on a 2 136g spinning HDDs. I'd like to replace both of them with 120G ssds.

When I use zfs replace rpool current-disk new-disk I get "cannot replace, device is too small.

As I understand it, ZFS should accept a smaller disk provided there's sufficient space on the new disk (the current boot drives are only at 2%).

What am I doing wrong?

 

[fabian]

you understand wrong, the disk you pass must be at least as big as the old one for a direct replacement. else, if you have the option to put in all disks you could also create a new pool and zfs send/recv your datasets over. but that requires a bit of downtime and knowledge of zpool/zfs commands.

 

[oguruma]

On this install, the VMs themselves live on a different pool, so it's only the Proxmox install that's on the boot pool.