how to setup disk redundancy with BTRFS filesystem
Starting with a plain old one-disk configuration… # df -h Filesystem Size Used Avail Use% Mounted on /dev/sda2 5.8G 590M 5.0G 11% /data thanks to the power of btrfs, let’s add a second hard disk, with mirrored data AND without unmounting/reformatting! :) also note the different size…. # fdisk -l Disk /dev/sda: 6 GiB, 6442450944 bytes, 12582912 sectors Units: sectors of 1 * 512 = 512 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disklabel type: dos Disk identifier: 0xea97ecdc Device Boot Start End Blocks Id System /dev/sda1 2048 526335 262144 82 Linux swap / Solaris /dev/sda2 * 526336 12582911 6028288 83 Linux Disk /dev/sdb: 4 GiB, 4294967296 bytes, 8388608 sectors Units: sectors of 1 * 512 = 512 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes … state of the filesystem before the change…...