Starting use of btrfs

So I had this "new" 200GB PATA disk to play with.  I started with some reading from howtoforge and created my first btrfs partition on it.  Initially I formatted the entire disk (/dev/sda) like this:

mkfs.btrfs /dev/sda

Then I changed my mind and recreated a partition table and a primary partition just for clarity.  It doesn't seem to help much but it also doesn't seem to be a problem and I reformatted using:

mkfs.btrfs /dev/sda1

So far so good.   186GB available.  I updated /etc/fstab to use the new btrfs partition for urBackup data and activating lzo compression on it:

UUID=5b775601-11bb-42d9-8b43-e106fb288c8e /var/backup/urBackup    btrfs compress=lzo 0 2

I moved the contents of my 300GB ext4 partition there after stopping the urBackup service:

sudo service urbackupsrv stop

Then restarted urBackup and checked it was running fine.  However I had to first change the permissions because urBackup runs as a normal user:

sudo chown urbackup:urbackup /var/backup/urBackup/

At this point the urBackup service seems to be happy from its new home:

sudo service urbackupsrv status
urbackupsrv.service - LSB: Server for doing backups
   Loaded: loaded (/etc/init.d/urbackupsrv; generated; vendor preset: enabled)
   Active: active (running) since Sat 2018-01-20 12:15:56 CET; 14min ago
     Docs: man:systemd-sysv-generator(8)
  Process: 1131 ExecStart=/etc/init.d/urbackupsrv start (code=exited, status=0/S
    Tasks: 25 (limit: 4915)
   CGroup: /system.slice/urbackupsrv.service
           └─1301 /usr/bin/urbackupsrv run --config /etc/default/urbackupsrv --d

jan 20 12:15:50 kid2.lan systemd[1]: Starting LSB: Server for doing backups...
jan 20 12:15:56 kid2.lan systemd[1]: Started LSB: Server for doing backups.
jan 20 12:16:51 kid2.lan urbackupsrv[1301]: Login successful for admin from 192.
jan 20 12:19:52 kid2.lan urbackupsrv[1301]: Login successful for admin from 127.

From there I recycled my 300GB SATA hard disk and added it to the btrfs pool, thus making it a multivolume filesystem:

sudo btrfs device add -f /dev/sdb1 /var/backup/urBackup

 Pretty happy at this  point.  Even more available space:

sudo btrfs filesystem show

Label: none  uuid: 5b775601-11bb-42d9-8b43-e106fb288c8e
    Total devices 2 FS bytes used 43.80GiB
    devid    1 size 186.31GiB used 2.01GiB path /dev/sda1
    devid    2 size 298.09GiB used 43.00GiB path /dev/sdb1

Or else:

df -h /dev/sda1
Sys. de fichiers Taille Utilisé Dispo Uti% Monté sur
/dev/sda1          485G     44G  440G  10% /var/backup/urBackup

The space above is shown after I had let urBackup run and soon after I had my backups done from the two Windows clients that are defined.  Can't wait now to add a third, bigger hard disk to this filesystem...