In the firsts tests fs ignore set values data_replicas_required=2 or
durability and metadata_target=rammeta.
On step 4 data count of replicas 1 (data_replicas_required=2 ignored or
wrong count foreground_target with durability=0 as second replica),
completely ignore meta_target (usage 0).
On step 5 strange percent of rereplicate and 163 MiB of data stay with 1
replica and partial cached metadata on zram2.
kernel 6.7.5
bcachefs-tools 1.6.3
full bcachefs usage -h attached
1) Create:
zramctl -a lzo-rle -s 32G /dev/zram2
zramctl -a lzo-rle -s 32G /dev/zram3
bcachefs format \
--data_replicas=2 --data_replicas_required=2 \
--metadata_replicas=2 --metadata_replicas_required=2 \
--compression=zstd:3 \
--background_compression=zstd:9 \
--label=hdd.01 --durability=1 /dev/mapper/sdk_cr \
--label=hdd.02 --durability=1 /dev/mapper/sdl_cr \
--label=rammeta.cache --durability=0 --discard /dev/zram2 \
--label=ramdata.cache --durability=0 --discard /dev/zram3 \
--metadata_target=rammeta \
--foreground_target=ramdata \
--promote_target=ramdata \
--background_target=hdd
mount -tbcachefs -ojournal_flush_disabled,discard
/dev/mapper/sdk_cr:/dev/mapper/sdl_cr:/dev/zram2:/dev/zram3 /mnt/bcachefs/
bcachefs usage -h
Size: 6.75 TiB
Used: 4.52 GiB
Online reserved: 0 B
Data type Required/total Durability Devices
btree: 1/2 2 [dm-20 dm-21] 10.0 MiB
2) create subvolume s1
3) create subvolume s1/s2
4) rsync some data ->s1/s2
bcachefs usage -h
Filesystem: 9d284190-ab97-4e27-9d73-d1ec5ae4c55b
Size: 6.75 TiB
Used: 14.4 GiB
Online reserved: 0 B
Data type Required/total Durability Devices
btree: 1/2 2 [dm-20 dm-21] 445 MiB
user: 1/1 1 [dm-20] 9.46 GiB
cached: 1/1 0 [zram3] 9.46 GiB
zram2 - empty
strange replication
8k/s random disk activity (journal?)
5) bcachefs data rereplicate
....
113% complete: current position user extents:805306913:1028608
....
187% complete: current position user extents:1275075211:3142912
....
238% complete: current position user extents:1946157064:16
Done
bcachefs usage -h
Filesystem: 9d284190-ab97-4e27-9d73-d1ec5ae4c55b
Size: 6.75 TiB
Used: 23.9 GiB
Online reserved: 0 B
Data type Required/total Durability Devices
btree: 1/2 2 [dm-20 dm-21] 623 MiB
user: 1/2 2 [dm-20 dm-21] 18.6 GiB
user: 1/1 1 [dm-20] 163 MiB <<<---
strange
cached: 1/1 0 [zram3] 9.47 GiB
cached: 1/1 0 [zram2] 81.5 MiB <<<---
meta partial cached?
--
Michael
Filesystem: 9d284190-ab97-4e27-9d73-d1ec5ae4c55b
Size: 6.75 TiB
Used: 4.52 GiB
Online reserved: 0 B
Data type Required/total Durability Devices
btree: 1/2 2 [dm-20 dm-21] 10.0 MiB
hdd.01 (device 0): dm-20 rw
data buckets fragmented
free: 3.64 TiB 15253502
sb: 3.00 MiB 13 252 KiB
journal: 2.00 GiB 8192
btree: 5.00 MiB 20
user: 0 B 0
cached: 0 B 0
parity: 0 B 0
stripe: 0 B 0
need_gc_gens: 0 B 0
need_discard: 0 B 0
capacity: 3.64 TiB 15261727
hdd.02 (device 1): dm-21 rw
data buckets fragmented
free: 3.64 TiB 15253502
sb: 3.00 MiB 13 252 KiB
journal: 2.00 GiB 8192
btree: 5.00 MiB 20
user: 0 B 0
cached: 0 B 0
parity: 0 B 0
stripe: 0 B 0
need_gc_gens: 0 B 0
need_discard: 0 B 0
capacity: 3.64 TiB 15261727
ramdata.cache (device 3): zram3 rw
data buckets fragmented
free: 31.7 GiB 130035
sb: 3.00 MiB 13 252 KiB
journal: 256 MiB 1024
btree: 0 B 0
user: 0 B 0
cached: 0 B 0
parity: 0 B 0
stripe: 0 B 0
need_gc_gens: 0 B 0
need_discard: 0 B 0
capacity: 32.0 GiB 131072
rammeta.cache (device 2): zram2 rw
data buckets fragmented
free: 31.7 GiB 130035
sb: 3.00 MiB 13 252 KiB
journal: 256 MiB 1024
btree: 0 B 0
user: 0 B 0
cached: 0 B 0
parity: 0 B 0
stripe: 0 B 0
need_gc_gens: 0 B 0
need_discard: 0 B 0
capacity: 32.0 GiB 131072
Filesystem: 9d284190-ab97-4e27-9d73-d1ec5ae4c55b
Size: 6.75 TiB
Used: 14.4 GiB
Online reserved: 0 B
Data type Required/total Durability Devices
btree: 1/2 2 [dm-20 dm-21] 445 MiB
user: 1/1 1 [dm-20] 9.46 GiB
cached: 1/1 0 [zram3] 9.46 GiB
hdd.01 (device 0): dm-20 rw
data buckets fragmented
free: 3.63 TiB 15213868
sb: 3.00 MiB 13 252 KiB
journal: 2.00 GiB 8192
btree: 223 MiB 890
user: 9.46 GiB 38764 28.0 KiB
cached: 0 B 0
parity: 0 B 0
stripe: 0 B 0
need_gc_gens: 0 B 0
need_discard: 0 B 0
capacity: 3.64 TiB 15261727
hdd.02 (device 1): dm-21 rw
data buckets fragmented
free: 3.64 TiB 15252632
sb: 3.00 MiB 13 252 KiB
journal: 2.00 GiB 8192
btree: 223 MiB 890
user: 0 B 0
cached: 0 B 0
parity: 0 B 0
stripe: 0 B 0
need_gc_gens: 0 B 0
need_discard: 0 B 0
capacity: 3.64 TiB 15261727
ramdata.cache (device 3): zram3 rw
data buckets fragmented
free: 22.3 GiB 91271
sb: 3.00 MiB 13 252 KiB
journal: 256 MiB 1024
btree: 0 B 0
user: 0 B 0
cached: 9.46 GiB 38764
parity: 0 B 0
stripe: 0 B 0
need_gc_gens: 0 B 0
need_discard: 0 B 0
capacity: 32.0 GiB 131072
rammeta.cache (device 2): zram2 rw
data buckets fragmented
free: 31.7 GiB 130035
sb: 3.00 MiB 13 252 KiB
journal: 256 MiB 1024
btree: 0 B 0
user: 0 B 0
cached: 0 B 0
parity: 0 B 0
stripe: 0 B 0
need_gc_gens: 0 B 0
need_discard: 0 B 0
capacity: 32.0 GiB 131072
Filesystem: 9d284190-ab97-4e27-9d73-d1ec5ae4c55b
Size: 6.75 TiB
Used: 23.9 GiB
Online reserved: 0 B
Data type Required/total Durability Devices
btree: 1/2 2 [dm-20 dm-21] 623 MiB
user: 1/2 2 [dm-20 dm-21] 18.6 GiB
user: 1/1 1 [dm-20] 163 MiB
cached: 1/1 0 [zram3] 9.47 GiB
cached: 1/1 0 [zram2] 81.5 MiB
hdd.01 (device 0): dm-20 rw
data buckets fragmented
free: 3.63 TiB 15213513
sb: 3.00 MiB 13 252 KiB
journal: 2.00 GiB 8192
btree: 311 MiB 1245
user: 9.46 GiB 38764 28.0 KiB
cached: 0 B 0
parity: 0 B 0
stripe: 0 B 0
need_gc_gens: 0 B 0
need_discard: 0 B 0
capacity: 3.64 TiB 15261727
hdd.02 (device 1): dm-21 rw
data buckets fragmented
free: 3.63 TiB 15214119
sb: 3.00 MiB 13 252 KiB
journal: 2.00 GiB 8192
btree: 311 MiB 1245
user: 9.32 GiB 38158 236 KiB
cached: 0 B 0
parity: 0 B 0
stripe: 0 B 0
need_gc_gens: 0 B 0
need_discard: 0 B 0
capacity: 3.64 TiB 15261727
ramdata.cache (device 3): zram3 rw
data buckets fragmented
free: 22.2 GiB 91000
sb: 3.00 MiB 13 252 KiB
journal: 256 MiB 1024
btree: 0 B 0
user: 0 B 0
cached: 9.47 GiB 39035
parity: 0 B 0
stripe: 0 B 0
need_gc_gens: 0 B 0
need_discard: 0 B 0
capacity: 32.0 GiB 131072
rammeta.cache (device 2): zram2 rw
data buckets fragmented
free: 31.7 GiB 129709
sb: 3.00 MiB 13 252 KiB
journal: 256 MiB 1024
btree: 0 B 0
user: 0 B 0
cached: 81.5 MiB 326
parity: 0 B 0
stripe: 0 B 0
need_gc_gens: 0 B 0
need_discard: 0 B 0
capacity: 32.0 GiB 131072
