NAS326 500 Internal Server Error

I pm'ed you a downloadlink to a statically linked version of ddrescue. To use it, you'll have to put the defective disk together with a new disk in the NAS. Then find out the device names of both disks.

cat /proc/partitions

will show all block devices, which are disks, partitions, raid arrays and flash partitions. sda is a disk, sda1 is the first partition on that disk. sdb is the second disk. I expect the old disk to have 2 partitions, the first about 2GB (about 2000000 blocks), and the second the rest of the disk. The new disk is probably empty, as in, having no partitions.

Use winscp to transfer ddrescue to /tmp/. Then execute

chmod a+x /tmp/ddrescue.arm7l
/tmp/ddrescue.arm7l /dev/sda /dev/sdb

where sda is the old disk, and sdb is the new disk. Doublecheck that sda is indeed the old disk, and sdb the new one. ddrescue will overwrite anything you specify as target, without asking. If you do it the wrong way, your data is gone forever.

The copy will take hours, (at best it can do +/- 75MB sec, but if the source disk is difficult to read ddrescue will spent extra time to try again, and worst case it can take days.) During that time the ssh shell needs to stay open. So take precautions you PC/laptop will not go in sleep mode.

During the copy ddrescue will provide information about the progress.

When copying is done, you can pull the old disk, and theoretically the NAS won't notice the disk was exchanged.