A small script to test zfs raid-z expansion in Solus Linux (requires root user)
#!/bin/sh
ZPOOL="/usr/local/sbin/zpool"
truncate -s 1G FILE0
truncate -s 1G FILE1
truncate -s 1G FILE2
truncate -s 1G FILE3
truncate -s 1G FILE4
losetup /dev/loop0 FILE0
losetup /dev/loop1 FILE1
losetup /dev/loop2 FILE2
losetup /dev/loop3 FILE3
losetup /dev/loop4 FILE4
$ZPOOL create RAID5 raidz loop0 loop1 loop2 loop3
# Copy a small amount of data on to the new filesystem
# (Update if not using Solus Linux)
cp -a /usr/lib64/budgie-desktop /RAID5/test
$ZPOOL status RAID5
# Expand that vdev
$ZPOOL attach RAID5 raidz1-0 loop4
$ZPOOL status RAID5
sleep 10
$ZPOOL status RAID5
$ZPOOL destroy RAID5
losetup --detach /dev/loop0
losetup --detach /dev/loop1
losetup --detach /dev/loop2
losetup --detach /dev/loop3
losetup --detach /dev/loop4
rm FILE?