Testing btrfs dup profile and automatic repairing on a USB drive.
$ sudo mkfs.btrfs -d dup -m dup -L Dati /dev/sdc1 -f
btrfs-progs v6.16.1
See https://btrfs.readthedocs.io for more information.
Label: Dati
UUID: 9598b427-857e-44c7-9800-dbd90bd7cbe7
Node size: 16384
Sector size: 4096 (CPU page size: 4096)
Filesystem size: 57.73GiB
Block group profiles:
Data: DUP 1.00GiB
Metadata: DUP 1.00GiB
System: DUP 8.00MiB
SSD detected: no
Zoned device: no
Features: extref, skinny-metadata, no-holes, free-space-tree
Checksum: crc32c
Number of devices: 1
Devices:
ID SIZE PATH
1 57.73GiB /dev/sdc1
$ sudo mount | grep /dev/sdc1
/dev/sdc1 on /run/media/frafra/Dati type btrfs (rw,nosuid,nodev,relatime,space_cache=v2,subvolid=5,subvol=/,uhelper=udisks2)
$ echo "BITROT_TARGET_DATA_9999" > /run/media/frafra/Dati/rot.txt
$ sudo grep -abom 2 "BITROT_TARGET_DATA_9999" /dev/sdc
40361406:BITROT_TARGET_DATA_9999
1113644478:BITROT_TARGET_DATA_9999
$ sudo hexdump -C -s 40361406 -n 23 /dev/sdc
0267ddbe 42 49 54 52 4f 54 5f 54 41 52 47 45 54 5f 44 41 |BITROT_TARGET_DA|
0267ddce 54 41 5f 39 39 39 39 |TA_9999|
0267ddd5
$ sudo dd if=/dev/urandom of=/dev/sdc seek=40361406 count=10 bs=1 conv=notrunc
10+0 records in
10+0 records out
10 bytes copied, 6.5639e-05 s, 152 kB/s
$ sudo hexdump -C -s 40361406 -n 23 /dev/sdc
0267ddbe b6 99 c4 f1 78 2d 82 ca e0 c3 47 45 54 5f 44 41 |....x-....GET_DA|
0267ddce 54 41 5f 39 39 39 39 |TA_9999|
0267ddd5
$ cat /run/media/frafra/Dati/rot.txt
BITROT_TARGET_DATA_9999
$ sudo grep -abom 2 "BITROT_TARGET_DATA_9999" /dev/sdc
1113644478:BITROT_TARGET_DATA_9999
1114103230:BITROT_TARGET_DATA_9999