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How to create a RAID array with Btrfs?
Btrfs RAID is flexible also in the sense that you can either create the RAID array by running something like mkfs.btrfs -d raid1 -m raid1 /dev/sdb1 /dev/sdc1 when you create the partitions, or you can at any later time convert existing partitions to use RAID by running a command like btrfs balance start -dconvert=raid1 -mconvert=raid1 /home
Can a single device be used as a Btrfs Mount?
(See btrfs-space-calculator or btrfs disk usage calculator) Non-striped equivalents may give you a more effective use of space (single instead of RAID 0, RAID 1 instead of RAID 10). Once you create a multi-device filesystem, you can use any device in the FS for the mount command:
What does Btrfs device delete missing mean in raid XX?
btrfs device delete missing tells btrfs to remove the first device that is described by the filesystem metadata but not present when the FS was mounted. In case of RAID XX layout, you cannot go below the minimum number of the device required. So before removing a device (even the missing one) you may need to add a new one.
Which is better for raid, Btrfs or mdadm?
In RAID usage btrfs is much more flexible and space efficient than traditional mdadm, because in btrfs the disks in the RAID array do not conform to any predefined size or count requirements.
How to repair broken Btrfs of RAID1 / kernel?
From ‘man mount’: Mount options for btrfs […] degraded Allow mounts to continue with missing devices. A read-write mount may fail with too many devices missing, for example if a stripe member is completely missing. Post the output of dmesg following a failed degraded mount, and hope zero-log didn’t cause more problems.
What to do with a broken RAID array?
At least keep the usage to a minimum. Turn off or unplug the broken RAID set and carefully disconnect each hard drive from the RAID array. Place the drives somewhere safely. After disconnecting drives from RAID 0, RAID 5, or RAID 6 array, connect each drive to a Windows PC.