====== btrfs ======

===== btrfs on lotr =====
Use RAID1 and choose stronger checksum XXHASH64
<code>
root@lotr:~# mkfs.btrfs -d raid1 -L btrfs_lotr --checksum xxhash /dev/sda /dev/sdb
</code>

fstab like so
<code>
UUID=<the_uuid> /btrfs_root btrfs defaults,noatime 0       0
</code>

Installed btrfsmaintenance package and edited /etc/default/btrfsmaintenance since we are not mounted at /
<code>
BTRFS_BALANCE_MOUNTPOINTS="/btrfs_root"
BTRFS_SCRUB_MOUNTPOINTS="/btrfs_root"
BTRFS_TRIM_MOUNTPOINTS="/btrfs_root"
</code>

Enabled these timers
<code>
systemctl enable btrfs-balance.timer
systemctl enable btrfs-scrub.timer
</code>

And refreshed the configuration (unsure if it is needed or a reboot does the same)
<code>
systemctl restart btrfsmaintenance-refresh.service
</code>

Verified that timers were added to systemd
<code>
root@lotr:~# systemctl -t timer list-units 'btrfs*'
  UNIT                LOAD   ACTIVE SUB     DESCRIPTION
  btrfs-balance.timer loaded active waiting Balance block groups on a btrfs filesystem
  btrfs-scrub.timer   loaded active waiting Scrub btrfs filesystem, verify block checksums
</code>

Create subvolume for imagelib
<code>
btrfs su create /btrfs_root/imagelib
</code>

Setup fstab to mount subvolume separate from btrfs_root
<code>
UUID=<the_uuid> /imagelib btrfs defaults,noatime,subvol=imagelib 0       0
</code>