Pulled the disk and connected to my linux box:
- `e2fsck -fcck`: no bad sectors
- `dd if=... of=/dev/null bs=4K` on every file: no problems, healthy reading speed
Connected back RouterOS, run the "samba" container:
- `dd if=... of=/dev/null bs=4K` on every file: no problems, healthy reading speed
Then mounted the samba share and tried to copy the same files: the problem re-appeared, copying gets progressively slow as if there is some caching problem. What took 20s by `dd` takes tens of minutes and ETA just keeps growing.
So disk appears to be fine, veth speed appears to be fine, and samba container worked well before the update. Updating to 7.14.2 did not address the problem.
@anotnsb's advice to reformat drive doesn't seem to make sense: ext4 is ext4 and another linux box had no trouble reading. Here is the output of `dumpe2fs`:
dumpe2fs 1.46.2 (28-Feb-2021)
Filesystem volume name: <none>
Last mounted on: /shares/Movies
Filesystem UUID: b559b32c-5b64-4b39-94b6-2af5b009efee
Filesystem magic number: 0xEF53
Filesystem revision #: 1 (dynamic)
Filesystem features: has_journal ext_attr resize_inode dir_index filetype extent 64bit flex_bg sparse_super large_file huge_file dir_nlink extra_isize metadata_csum
Filesystem flags: unsigned_directory_hash
Default mount options: user_xattr acl
Filesystem state: clean
Errors behavior: Continue
Filesystem OS type: Linux
Inode count: 19537920
Block count: 78124992
Reserved block count: 3906249
Overhead clusters: 1505042
Free blocks: 58437717
Free inodes: 19537849
First block: 0
Block size: 4096
Fragment size: 4096
Group descriptor size: 64
Reserved GDT blocks: 1024
Blocks per group: 32768
Fragments per group: 32768
Inodes per group: 8192
Inode blocks per group: 512
Flex block group size: 16
Filesystem created: Tue Nov 28 21:28:06 2023
Last mount time: Fri Apr 5 23:28:19 2024
Last write time: Fri Apr 5 23:30:57 2024
Mount count: 0
Maximum mount count: -1
Last checked: Fri Apr 5 23:30:57 2024
Check interval: 0 (<none>)
Lifetime writes: 113 GB
Reserved blocks uid: 0 (user root)
Reserved blocks gid: 0 (group root)
First inode: 11
Inode size: 256
Required extra isize: 32
Desired extra isize: 32
Journal inode: 8
Default directory hash: half_md4
Directory Hash Seed: d4a44757-3ec8-4636-b197-5985d0e4f40a
Journal backup: inode blocks
Checksum type: crc32c
Checksum: 0x59f90789
Journal features: journal_incompat_revoke journal_64bit journal_checksum_v3
Total journal size: 1024M
Total journal blocks: 262144
Max transaction length: 262144
Fast commit length: 0
Journal sequence: 0x00002219
Journal start: 0
Journal checksum type: crc32c
Journal checksum: 0x5416847b
What to try next?