22tb hd: i/o device error & read error 27 & GPT damaged

my config:

uname -a: Linux GL-AR300M 4.14.241 #0 Thu Jul 29 19:50:28 2021 mips GNU/Linux
firmware: 3.216
OpenWrt 19.07.8

22TB hard disk attached to USB port, formatted with NTFS and GPT.

When trying to delete, create or edit files I get “i/o device error”

gdisk shows this error:

GPT fdisk (gdisk) version 1.0.4

Warning! Read error 27; strange behavior now likely!
Caution: invalid backup GPT header, but valid main header; regenerating
backup header from main header.

Warning! Error 27 reading partition table for CRC check!
Warning! One or more CRCs don't match. You should repair the disk!
Main header: OK
Backup header: ERROR
Main partition table: OK
Backup partition table: ERROR
Partition table scan:
  MBR: protective
  BSD: not present
  APM: not present
  GPT: damaged

Caution: Found protective or hybrid MBR and corrupt GPT. Using GPT, but disk
verification and recovery are STRONGLY recommended.

I did “w” write (to fix) the gpt table, as well as “r” recovery (b,c,d,e). The errors remain the same.

The hard disk works fine under linux and windows (at a laptop).

Any ideas?

The power draw of the disk drive is probably too high for AR300m to handle. Maybe try a powered USB hub.

I use an external hard disk case with with a power connection. The router can read the directory structure partially and read the contents of the files.

Is there anybody here who operates a large (>14TB) hard disk with the router?