Bad and reallocated sector count stuck at 9800

[Alfonico]

Hello.
Happy new year to all!

I have an external disk (Toshiba 2.5", normal plate disk, not SSD) that shows a lot of bad sectors on a limited part of the disk at the beginning. The rest of the disk is OK. I try to get rid of all the bad sectors, or in other words, to have these bad sectors not accessible, even if this means a reduced capacity of the disk.
I plan to use this disk for backup purposes only, and presently it doesn't contain any data.
Therefore I can use destructive tests.

When running self test and destructive tests, I have been progressively increasing the count of bad and reallocated sectors to reach 9800.

I keep testing the bad area of the disk, and I still detect bad sectors, but the count doesn't increase any more, it stays at 9800.

Is this 9800 a limit of the possible reallocations, indicating that all of the spare area of the disk has been used?

If this is the case:
- will the write and read destructive test be able to mark the bad sectors found by the test as "not to be accessed anymore", even if the spare area is already completely used (the actual capacity of the disk being then reduced by the amount of bad sectors not reallocated but made inaccessible)?
or
- these bad sectors cannot be eliminated anymore from the sectors that can be accessed and the hard disk section affected is therefore useless ?

Thanks and regards

[hdsentinel]

In this case "these bad sectors cannot be eliminated anymore from the sectors that can be accessed"

The destructive tests (eg. Disk menu -> Surface test -> Reinitialise Disk Surface) forces the disk drive to reallocate sectors: to replace them from spare area. Then the original bad sector would be no longer used and the spare sector would be read/written instead.

But yes, if the spare area is full - then no further reallocations possible. So in this case while 9800 sectors already fixed by the reallocation, no more reallocations possible: any further sectors remain uncorrectable and can risk data corruption / data loss.

Yes, if you create partition to different areas of the disk, then (in theory) there should be no problems as these sectors will be not read/written during normal use (however, the disk firmware can still access them eg. during a self test).

Let's say (for example) that Hard Disk Sentinel surface test shows these sectors between blocks 0-200 in (which means before 2% of the complete disk surface).

Then if you create a small partition in Windows Disk Management to cover this area (2% of the disk capacity) and then create a big data partition, then you can be safe. Then you can even delete the first small partition, as it was required only to fill the problematic area, but should be never used.
So then you can use the disk drive with reduced capacity.

Considering the amount of problems (I bet the health displayed in Hard Disk Sentinel is very low, for a good reason) I'd recommend to use only for non-critical data.

[Alfonico]

Many thanks. All clear!