Wrong cache size display

Known limitation with BTRFS not reporting correct sizes with mismatched drive sizes

With raid5 free space won't account for parity, even with same size devices, used space will be correct, total size is correct when using same size devices, so likely related to that, currently even btrfs tools don't display correct sizes when raid5/6 is used, though they working on fixing that, when that's fixed Unraid should also display correct values.

 

Quote

 

root@Tower7:~# btrfs fi usage -T /mnt/cache
WARNING: RAID56 detected, not implemented
Overall:
    Device size:                   5.46TiB
    Device allocated:             10.06GiB
    Device unallocated:            5.45TiB
    Device missing:                  0.00B
    Used:                          6.83GiB
    Free (estimated):                0.00B      (min: 8.00EiB)
    Data ratio:                       0.00
    Metadata ratio:                   2.00
    Global reserve:              512.00MiB      (used: 0.00B)

             Data      Metadata System
Id Path      RAID5     RAID1    RAID1     Unallocated
-- --------- --------- -------- --------- -----------
 1 /dev/sdc1 737.00GiB  1.00GiB  32.00MiB   193.48GiB
16 /dev/sdd1 737.00GiB  1.00GiB  32.00MiB   193.48GiB
 8 /dev/sde1 737.00GiB  2.00GiB         -   192.51GiB
13 /dev/sdf1 737.00GiB  2.00GiB         -   192.51GiB
 9 /dev/sdg1 737.00GiB  2.00GiB         -   192.51GiB
18 /dev/sdh1 737.00GiB  2.00GiB         -   192.51GiB
-- --------- --------- -------- --------- -----------
   Total       3.60TiB  5.00GiB  32.00MiB     1.13TiB
   Used        3.10TiB  3.42GiB 240.00KiB

 

 

Edited August 26, 2019 by johnnie.black