HOW TO - ZFS replace disk

Set variables

HEALTHY_DISK=/dev/sda
BROKEN_DISK=/dev/sdb

Make sure that the variables are correctly populated by executing this:

echo "HEALTHY_DISK: ${HEALTHY_DISK}"
echo "BROKEN_DISK: ${BROKEN_DISK}"

This should output

HEALTHY_DISK: /dev/sda
BROKEN_DISK: /dev/sdb

Check status
```
zpool status
```
List disks
```
lsblk | grep -v zd
```
Rescan partitions (if the disk was replaced while the system was online):
```
blockdev --rereadpt /dev/${BROKEN_DISK}
```

Copy partition layout from working disk to replaced disk:

sgdisk --backup=/tmp/sda.layout ${HEALTHY_DISK}
sgdisk --load-backup=/tmp/sda.layout ${BROKEN_DISK}

Resilver disk:
- FAILED_DISK_ID can be an ID or just the partition number (when online replaced)
- NEW_DISK_ID from the new disk or just the partition path (e.g. /dev/sdb3)
Recommended is to use the IDs. They can be found with:
```
ls -l /dev/disk/by-id/
```
```
zpool replace rpool <FAILED_DISK_ID> ${BROKEN_DISK}3
```
Copy data from BIOS boot partition to new one (if replaced disk was the boot disk):
```
dd if=${HEALTHY_DISK}1 of=${BROKEN_DISK}1 bs=512
```

Reinstall bootloader on replaced disk (if replaced disk was the boot disk):

GRUB

proxmox-boot-tool format ${BROKEN_DISK}2 --force
proxmox-boot-tool init ${BROKEN_DISK}2 grub

systemd-boot

proxmox-boot-tool format ${BROKEN_DISK}2 --force
proxmox-boot-tool init ${BROKEN_DISK}2

Update initramfs information (if replaced disk was the boot disk):
```
update-initramfs -u
proxmox-boot-tool status
```
List ZFS status again:
```
zpool status
```