HPR1228: Utilizing Maximum Space on a Cloned BTRFS Partition

Utilizing Maximum Space on a Cloned BTRFS Partition

by FiftyOneFifty

1. If you clone a disk to a disk, Clonezilla will increase (decrease) the size of each partition proportional to the relative size of the drives.
   1. I wanted to keep my / the same size and have no swap (new drive was SSD), so I did a partition to partition clone instead
   2. Created partitions on the new SSDs with a GParted Live CD, 12Gb root (Ext4) and the remainder for /home, (btrfs, because I planned to move to SSD from the start, and last summer only btrfs supported TRIM)
2. After cloning /dev/sda1 to /dev/sdb1 and /dev/sda2 to /dev/sdb2 using Clonezilla, I inspected the new volumes with the GParted Live CD
   1. /dev/sdb2 had 40% inaccessible space, i.e., the usable space was the same size as the old /home volume
   2. GParted flagged the error and said I could correct it from the menu (Partition->Check) but btrfs doesn't support fsck, so it didn't work
   3. Tried shrinking the volume in GParted and re-expanding it to take up the free space, also didn't work.
3. Discovered 'btrfs utility' and that it was supported by the GParted Live CD
   1. Make a mount point
      • sudo mkdir /media/btrfs
   2. Mount the btrfs volume
      • sudo mount /dev/sdb2 /media/btrfs
   3. Use btrfs utility to expand the btrfs file system to the maximum size of the volume
      • sudo btrfs filesystem resize max /media/btrfs
   4. Unmount the btrfs volume
      • sudo umount /dev/sdb2
4. Rechecked /dev/sdb2 with GParted, I no longer had inaccessible space

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