[nixos@nixos:~]$ sudo bcachefs show-super /dev/sda
Device:                                     Samsung SSD 860 
External UUID:                             becc93fe-5efb-4d02-9fcc-f0ce0b23a7c8
Internal UUID:                             5ab21e3e-9622-4082-975c-d060d674a340
Magic number:                              c68573f6-66ce-90a9-d96a-60cf803df7ef
Device index:                              3
Label:                                     (none)
Version:                                   1.20: directory_size
Incompatible features allowed:             0.0: (unknown version)
Incompatible features in use:              0.0: (unknown version)
Version upgrade complete:                  1.13: inode_has_child_snapshots
Oldest version on disk:                    1.12: rebalance_work_acct_fix
Created:                                   Sun Dec  1 10:49:02 2024
Sequence number:                           268
Time of last write:                        Sat May  3 18:26:25 2025
Superblock size:                           5.34 KiB/1.00 MiB
Clean:                                     1
Devices:                                   4
Sections:                                  members_v1,crypt,replicas_v0,disk_groups,clean,journal_seq_blacklist,journal_v2,counters,members_v2,errors,ext,downgrade
Features:                                  zstd,journal_seq_blacklist_v3,reflink,new_siphash,inline_data,new_extent_overwrite,btree_ptr_v2,extents_above_btree_updates,btree_updates_journalled,reflink_inline_data,new_varint,journal_no_flush,alloc_v2,extents_across_btree_nodes
Compat features:                           alloc_info,alloc_metadata,extents_above_btree_updates_done,bformat_overflow_done

Options:
  block_size:                              4.00 KiB
  btree_node_size:                         256 KiB
  errors:                                  continue [fix_safe] panic ro 
  write_error_timeout:                     30
  metadata_replicas:                       2
  data_replicas:                           2
  metadata_replicas_required:              1
  data_replicas_required:                  1
  encoded_extent_max:                      64.0 KiB
  metadata_checksum:                       none [crc32c] crc64 xxhash 
  data_checksum:                           none [crc32c] crc64 xxhash 
  checksum_err_retry_nr:                   3
  compression:                             none
  background_compression:                  zstd
  str_hash:                                crc32c crc64 [siphash] 
  metadata_target:                         none
  foreground_target:                       ssd
  background_target:                       hdd
  promote_target:                          ssd
  erasure_code:                            0
  inodes_32bit:                            1
  shard_inode_numbers_bits:                2
  inodes_use_key_cache:                    1
  gc_reserve_percent:                      8
  gc_reserve_bytes:                        0 B
  root_reserve_percent:                    0
  wide_macs:                               0
  promote_whole_extents:                   1
  acl:                                     1
  usrquota:                                0
  grpquota:                                0
  prjquota:                                0
  degraded:                                [ask] yes very no 
  journal_flush_delay:                     1000
  journal_flush_disabled:                  0
  journal_reclaim_delay:                   100
  journal_transaction_names:               1
  allocator_stuck_timeout:                 30
  version_upgrade:                         [compatible] incompatible none 
  nocow:                                   0

members_v2 (size 592):
Device:                                    0
  Label:                                   hdd1 (1)
  UUID:                                    3bc05e7a-81d9-4b88-ac83-dcc20ba85d7b
  Size:                                    16.4 TiB
  read errors:                             0
  write errors:                            0
  checksum errors:                         0
  seqread iops:                            0
  seqwrite iops:                           0
  randread iops:                           0
  randwrite iops:                          0
  Bucket size:                             256 KiB
  First bucket:                            0
  Buckets:                                 68665344
  Last mount:                              Sat May  3 18:26:25 2025
  Last superblock write:                   268
  State:                                   rw
  Data allowed:                            journal,btree,user
  Has data:                                journal,btree,user
  Btree allocated bitmap blocksize:        512 MiB
  Btree allocated bitmap:                  0000000000000000000000000100000000000000000000000000000100000001
  Durability:                              1
  Discard:                                 0
  Freespace initialized:                   1
  Resize on mount:                         0
Device:                                    1
  Label:                                   hdd2 (2)
  UUID:                                    a2b11511-4ccd-4f1b-8341-3ce90c251aad
  Size:                                    16.4 TiB
  read errors:                             0
  write errors:                            0
  checksum errors:                         0
  seqread iops:                            0
  seqwrite iops:                           0
  randread iops:                           0
  randwrite iops:                          0
  Bucket size:                             256 KiB
  First bucket:                            0
  Buckets:                                 68665344
  Last mount:                              Sat May  3 18:26:25 2025
  Last superblock write:                   268
  State:                                   rw
  Data allowed:                            journal,btree,user
  Has data:                                journal,btree,user
  Btree allocated bitmap blocksize:        128 MiB
  Btree allocated bitmap:                  0000000000000000000000001000000000000000000000000000000000001101
  Durability:                              1
  Discard:                                 0
  Freespace initialized:                   1
  Resize on mount:                         0
Device:                                    2
  Label:                                   ssd1 (4)
  UUID:                                    c44f471f-5c96-4370-a0ed-745e9e5248a6
  Size:                                    215 GiB
  read errors:                             0
  write errors:                            0
  checksum errors:                         0
  seqread iops:                            0
  seqwrite iops:                           0
  randread iops:                           0
  randwrite iops:                          0
  Bucket size:                             256 KiB
  First bucket:                            0
  Buckets:                                 880930
  Last mount:                              Sat May  3 18:26:25 2025
  Last superblock write:                   268
  State:                                   rw
  Data allowed:                            journal,btree,user
  Has data:                                cached
  Btree allocated bitmap blocksize:        1.00 B
  Btree allocated bitmap:                  0000000000000000000000000000000000000000000000000000000000000000
  Durability:                              0
  Discard:                                 1
  Freespace initialized:                   1
  Resize on mount:                         0
Device:                                    3
  Label:                                   ssd2 (5)
  UUID:                                    5226b956-3a79-41e2-b29a-40bcceb37707
  Size:                                    932 GiB
  read errors:                             0
  write errors:                            0
  checksum errors:                         0
  seqread iops:                            0
  seqwrite iops:                           0
  randread iops:                           0
  randwrite iops:                          0
  Bucket size:                             256 KiB
  First bucket:                            0
  Buckets:                                 3815478
  Last mount:                              Sat May  3 18:26:25 2025
  Last superblock write:                   268
  State:                                   rw
  Data allowed:                            journal,btree,user
  Has data:                                cached
  Btree allocated bitmap blocksize:        1.00 B
  Btree allocated bitmap:                  0000000000000000000000000000000000000000000000000000000000000000
  Durability:                              0
  Discard:                                 1
  Freespace initialized:                   1
  Resize on mount:                         0

errors (size 8):