I have a btrfs filesystem for which the output of
btrfs fi usage /mnt is:
Overall: Device size: 60.00GiB Device allocated: 40.00GiB Device unallocated: 20.00GiB Device missing: 0.00B Used: 38.03GiB Free (estimated): 10.00GiB (min: 10.00GiB) Data ratio: 2.00 Metadata ratio: 2.00 Global reserve: 22.00MiB (used: 0.00B) Data,RAID1: Size:18.99GiB, Used:18.99GiB /dev/sdb 18.99GiB /dev/sdc 18.99GiB Metadata,RAID1: Size:1.00GiB, Used:22.11MiB /dev/sdb 1.00GiB /dev/sdc 1.00GiB System,RAID1: Size:8.00MiB, Used:16.00KiB /dev/sdb 8.00MiB /dev/sdc 8.00MiB Unallocated: /dev/sdb 1.00MiB /dev/sdc 1.00MiB /dev/sdd 20.00GiB
As you can see, all allocated data chunks are completely full.
btrfs balance start /mnt fails with:
ERROR: error during balancing '/mnt': No space left on device There may be more info in syslog - try dmesg | tail
This is not a duplicate of this question, which is about metadata chunks being full. My question is how do I get btrfs to allocate some chunks on