How to setup RAID

Pioneer Support
21

Indeed! I finally found some time to make progress:

btrfs replace start -B /dev/mmcblk0p2 /dev/sda1 /
btrfs filesystem resize max /
reboot

moved the file system to the new ssd. I also managed to set up a btrfs RAID 1 on my two 1TB HDD’s connected via USB. After creating two empty partitions on /dev/sdb and /dev/sdc (I used Cockpit for this) I did:

mkfs.btrfs -L "Nas" /dev/sdb -f 
mkfs.btrfs /dev/sdc -f
mkdir /mnt/nas
mount /dev/sdb /mnt/nas
cd /mnt/nas
btrfs subvolume create backup
cd
umount /dev/sdb
mount -o compress=zlib,subvol=backup,autodefrag,noatime /dev/sdb /mnt/nas
umount /dev/sdc
btrfs device add -f /dev/sdc /mnt/nas
btrfs filesystem balance start -dconvert=raid1 -mconvert=raid1 /mnt/nas
btrfs filesystem show /mnt/nas

With the help of northerncoder.ca.
Then set up Samba to back up my Windows 10 Box. Then backed up my Linux box with rsync. So far everything works as expected.

22

One small caveat. After setting up the above structure I found out that my Nas got mounted twice, first by /etc/fstab as /mnt/nas and then by the freedombox automount feature as /media/root/Nas. With the difference, that /mnt/nas pointed to the subvolume backup and /media/root/Nas to the root of /dev/sdb1.
I found this confusing as it also appeared twice on the Samba service page, as Nas and nas resp. So because of my setup I decided that I don’t need the automatic mount of removable devices and to remove the udisk2 service:

systemctl mask udisks2
systemctl unmask udisks2
systemctl unmask udisks2.service

Not sure if the last one is needed, though. Found at StackExchange.

23

Concerning the default mount, I learned that it can be handy to have the filesystem’s root mounted, to create snapshots and to have all subvolumes accessible for the root user, independent of custom mountpoint(s).

24

You didn’t write about the initial mkfs.btrfs of sdb.
Anyway nice that “show” seems to return your desired setup.

25

You’re right, of course, thank you. I edited my previous post.

26

Thank you for the hint, I didn’t consider this. If need be, I’ll undo the above removing of udisks2 service.