Pending Sectors gone after full format, but Reallocated count remains zero

[deathlyhall0ws]

Hi!

Pending Sectors showed up on one of my drives recently and started to increase until reaching 34, but none were getting reallocated and a couple of files were corrupted.

Today I did a full format which dropped the Pending count to zero, but the reallocated count also remains at zero.. So where did they go? Was it just some sort of error, or are they still there but hidden somehow? Is there any test I can run to figure out what's happening?

 

[Shaun o]

This is what happens in case your not aware.

Every hard drive has a set of spare sectors available to it, to recover any corrupt data from hard damaged sectors of the magnetic disk platter of the HD.

If the Sector in question is growing weak in it`s magnetic field the data is copied to a new good or well known sector of the drive pulled as redundancy protection.

The sectors are not infinite though, on average you may get up to 50 spare sectors provided on most mechanical hard drives.
In case ones in use holding data start to fail.

Once the spares are used up, then the amount of hard sector errors increase over time as the magnetic disk platter fails.

Once a hard error of a sector is detected it is flagged that under no condition is the sector ever to be used or accessed again by the drives read and write heads, and the mapped location of it.

This condition is held even if the drive is formatted, and instead of the drive showing the errors after the format of the drive is complete the size of the storage capacity simply shrinks.

I hope it explains why the sector, or Pending is back to 0 for both values.

 

[deathlyhall0ws]

This is what happens in case your not aware.

Every hard drive has a set of spare sectors available to it, to recover any corrupt data from hard damaged sectors of the magnetic disk platter of the HD.

If the Sector in question is growing weak in it`s magnetic field the data is copied to a new good or well known sector of the drive pulled as redundancy protection.

The sectors are not infinite though, on average you may get up to 50 spare sectors provided on most mechanical hard drives.
In case ones in use holding data start to fail.

Once the spares are used up, then the amount of hard sector errors increase over time as the magnetic disk platter fails.

Once a hard error of a sector is detected it is flagged that under no condition is the sector ever to be used or accessed again by the drives read and write heads, and the mapped location of it.

This condition is held even if the drive is formatted, and instead of the drive showing the errors after the format of the drive is complete the size of the storage capacity simply shrinks.

I hope it explains why the sector, or Pending is back to 0 for both values.

But if that's the case, shouldn't those sectors show up under Offline Uncorrectable? Both that one and Reallocated Sector Count are showing up as zero.

 

[Solandri]

I believe "pending sector" just means the sector experienced a read/write failure and has been put onto a "suspected bad" list. And if a subsequent write and read encounters no problems, the sector is removed from the list.

There may have been a transitory factor (maybe temperature?) which caused the sectors to originally fail. And when the conditions changed, the sectors worked again and the disk marked them as OK.

Edit: Acronis seems to agree.
https://kb.acronis.com/content/9133

 

[rkzhao]

Some firmware will remove a sector from the pending count if it succeeds on a retry instead of just remapping it. Generally speaking, the best way to force a reallocation is to overwrite the sector. The easiest way to do that is to use a "write zeros" type of full disk erase.

 

[deathlyhall0ws]

I believe "pending sector" just means the sector experienced a read/write failure and has been put onto a "suspected bad" list. And if a subsequent write and read encounters no problems, the sector is removed from the list.

There may have been a transitory factor (maybe temperature?) which caused the sectors to originally fail. And when the conditions changed, the sectors worked again and the disk marked them as OK.

Edit: Acronis seems to agree.
https://kb.acronis.com/content/9133

Ah, so pending doesn't necessarily mean it's a bad sector. Makes sense.
I'll keep a close eye on it and see if it happens again.

Some firmware will remove a sector from the pending count if it succeeds on a retry instead of just remapping it. Generally speaking, the best way to force a reallocation is to overwrite the sector. The easiest way to do that is to use a "write zeros" type of full disk erase.

That's basically what I did. A full format in win7 writes zeros to the disk.