Question SMART - Current Pending Sector Count

[valoryea]

I recently ran CrystalDiskInfo and found my WD Blue WD10EZEX-00WN4A0 (1TB) with a warning for Current Pending Sector Count.

https://imgur.com/a/jOBlJzI

View: https://imgur.com/a/jOBlJzI


Appears that is a warning for imminent failure and better to replace the disk, which I did.

Plugging the disk to another computer, I ran chkdsk and it got stuck 13% of stage 4 for a very long time while hogging 13GB of RAM. After perhaps an hour later it released and reported that "The disk does not have enough space to replace bad clusters" which suggests there're more bad sectors than there are reserved sectors to compensate.

Strangely enough, a second chkdsk overnight did manage to complete the whole process.

I:\>chkdsk /x /r
The type of the file system is NTFS.
Cannot lock current drive.
Volume dismounted. All opened handles to this volume are now invalid.
Volume label is Develop.

CHKDSK is verifying files (stage 1 of 5)...
540672 file records processed.
File verification completed.
315 large file records processed.
0 bad file records processed.
0 EA records processed.
0 reparse records processed.
CHKDSK is verifying indexes (stage 2 of 5)...
695064 index entries processed.
Index verification completed.
0 unindexed files scanned.
0 unindexed files recovered.
CHKDSK is verifying security descriptors (stage 3 of 5)...
540672 file SDs/SIDs processed.
Security descriptor verification completed.
77197 data files processed.
CHKDSK is verifying Usn Journal...
29200 USN bytes processed.
Usn Journal verification completed.
CHKDSK is verifying file data (stage 4 of 5)...
540656 files processed.
File data verification completed.
CHKDSK is verifying free space (stage 5 of 5)...
68508001 free clusters processed.
Free space verification is complete.
CHKDSK discovered free space marked as allocated in the volume bitmap.
Windows has made corrections to the file system.

976760828 KB total disk space.
701726964 KB in 349528 files.
118276 KB in 77198 indexes.
4 KB in bad sectors.
883580 KB in use by the system.
65536 KB occupied by the log file.
274032004 KB available on disk.

4096 bytes in each allocation unit.
244190207 total allocation units on disk.
68508001 allocation units available on disk.

And reports only 4KB bad. So what happened the previous round? I downloaded and run Western Digital's own Data LifeGuard Diagnostics tool and it didn't regard the Current Pending Sector Count as worrisome.

https://imgur.com/a/fpy9I5P

View: https://imgur.com/a/fpy9I5P


So who/which is correct on the matter? Is that 200 value bad or trivial? Another thing of note is I have an older 1TB WD10EALX-009BA0 which also has a Current Pending Sector Count value of 200 but is considered safe by CrystalDiskInfo. Most of the values between the disks are the same. Or is that an indication that the older disk has more reserved space than the newer model?

 

[PC Tailor]

Have you since rechecked the SMART status of the drive?

The current pending sector count is a reflection of how many sectors are waiting to be remapped after an issue was identified with them.

The CHKDSK will often attempt to remap these or reallocate them depending on the outcome, if they reallocate, your reallocated sectors count will rise, if the CHKDSK is able to read/write from them successfully again, it will remove the pending sector count and continue using the sector normally. So if the CHKDSK has been able to read/write from the sectors again, it would make sense that your pending sectors has gone down.

Also remember that one sector is usually 512 bytes, so 4KB isn't a lot in the long rung, but it is equivalent to 4000 bytes or 7/8 sectors

 

[valoryea]

My drives are typically formatted with NTFS so their default sector size is 4KB.

Do you mean the disk only has 4KB available for bad sectors? I understood from the results that the disk already has 4KB recognised as bad (1 sector). Or is that supposed to be interpreted differently?

So the thing now is, CrystalDiskInfo will report that as warning, while WD DLGDIAG regards it as normal.

C5 Current Pending Sector Count: Current = 200; Worst = 200; Threshold = 0

Now the difference is CrystalDiskInfo has a Raw value of 1 which is probably the thing that's setting off alarm bells. WD DLGDIAG on the other hand does not show such a parameter, but instead has a Warranty column of 0.

 

[valoryea]

I just completed a 2-pass zeroing format with format.exe, and now CrystalDiskInfo does not complain anymore. Bad sector will probably come back again though...

 

[PC Tailor]

Now the difference is CrystalDiskInfo has a Raw value of 1 which is probably the thing that's setting off alarm bells.

This would make sense if your sector size if 4KB - because the 4KB in CHKDSK is how many bad sectors were found, if the sector size is 4KB, then it found 1 bad sector.

If your format has cleared up the bad sector, then it could well be just a logical bad sector, whereby the contents of the cell differed from the expectation, or it timed-out when reading or writing the cell. Logical ones can be a one off, sometimes they can return if there is an underlying physical problem.

For now though, I'd say your fine, just keep an eye on the bad sectors count to see if any return as usually once they crop up, they only get worse. Regardless, I would keep a backup anyway.

 

[mdd1963]

Often quoted wIsdom among many is that perhaps 1 reallocated/bad sector can be 'forgiven'/lived with for home use, if no others start following/dropping like flies afterward...(if this were in a RAID 5, it might not be as livable, as one glitch with an additional drive during a stressful array rebuild after a full hard disk failure can result in loss of all data...)

I've seen 8 year old drives with 4-10 bad sectors still doing fine for 2 years afterward..

The first time you count on that, you'll likely soon learn that...you shouldn't have!

I sure would not trust it with your most sensitive and important data!

 

[valoryea]

Regardless, I would keep a backup anyway.

Yes experience has taught me to perform daily whole-partition backups on a daily basis. I've already bought a new 2TB disk over the weekend to restore partitions (also from another Seagate disk) to. Restoration is easy, but takes heck of a long time.

In fact experience has also taught me not to rely on solely one computer. All these extra testing and formatting were performed via my gaming computer, while my original work computer was undergoing image restoration and re-backup.