Reallocated Sectors Count keeps growing

[Zafar Iqbal]

Hi,

I just purchased a license after a friend of mine praised HD Sentinel - I have been using CrystalDiskInfo to keep track of my disks and noticed recently, that a disk within very short time-period (days), started to have issues with Reallocated Sector Count. I first sent the disk to my friend to have a look at it.

All data is backed up and I didn't encounter any apparent issues while doing so. The disk is a 4TB drive and had some 150GB available space on it.

My friend did a full Write and then a full Read test and he told me all sectors/blocks were green. No damaged or bad sectors were reported, however he noticed few blocks at the end not being same color and this is also when HDS started to log reallocated sectors. He then did isolated tests on those last blocks only, maybe 5-6 times and each time the Reallocated Sectors Count would grow.

I've been doing some Write tests myself, 3-4 so far, and same thing is happening here. The total amount of reallocated sectors is currently 15360 and the number just keeps growing every time I do a Write/Reinitialize test. Nothing bad is reported when doing a Read test. I've read it is recommended to do tests multiple times to see if a disk is stable, but how many times would that be?

I've also been doing a lot of reading and my head is about to explode now. There is lot's a different and even contradicting info out there, so now I'm not sure at all where I stand with this disk.

Should I replace it? Or can I partition it in a such way, that I do not use the last bit of it and from thereon reliably use it? The estimated remaining lifetime is at 12 days according to HD Sentinel.

I haven't done the Reinitialize test as it requires some 350+ hours.

Ps. The disk is just about a year old (312 days of power on time) - do you think the warranty would cover it?

[hdsentinel]

Thanks for your message and thanks for selecting Hard Disk Sentinel.

Yes, the Disk menu -> Surface test functions are the best way to diagnose and fix problems related to the hard disk.

If these surface tests show no red or yellow blocks, yes, it means that the hard disk is generally usable, all sectors could be accessed now.
But the darker green area indicates that those blocks are slower than expected, the hard disk may hard(er) to process them and this may even indicate increasing error count. Usually some such blocks are acceptable, but if they form continuous area(s), they can cause troubles.
Please check the end of the Help -> Hard Disk Tests -> Surface Tests section (online at http://www.hdsentinel.com/help/en/61_surfacetest.html ) for more details, it shows some examples.


Yes, the write tests (and especially the Reinitialise Disk Surface test) should force the hard disk to repair those sectors (if required): to replace them with sectors from the spare area. This way the original sectors would be no longer used and then the spare sectors would be read/written later.

Just as you can see, sometimes even if reallocations happen, other sectors (usually neighbour sectors of the original sectors which reallocated) may also begin to fail. So repeated tests force the hard disk to reallocate more and more sectors.

As each problems / failures different, it is hard to say a sure repeat count. In most cases one Reinitialise Disk Surface test should be enough, but it is possible that new and new reallocated sectors reported even after re-running the test 5-10 times or more, depending on the amount of sectors should (and could) be reallocated by the hard disk.

This procedure can continue until the hard disk status become really stable (no further rallocations happen), the spare area become full - or (worst case) if the hard disk fail completely.

In theory, in such situations, the manufacturers may not offer warranty replacement. They may perform a read scan and give back the hard disk as "perfect" as they may not care about possible slower areas and/or increased error count. Generally, warranty replacement is possible only when the amount of problems reach the error-level threshold set by the manufacturer, when the health drops to 0% in Hard Disk Sentinel.
But according the experiences, nowadays manufacturers may provide replacement of the drive even in such situation, when the error-counter(s) are really high.
It is possible that some additional write tests will cause the error-count to increase further to reach the threshold and then you can surely ask for warranty replacement.

Yes, exactly as you wrote, if you prefer to continue using it, the best would be to partition the hard disk in a way that the problematic sectors should be outside the partition. So in theory, the hard disk will never use the affected sectors and then the reallocated sector count may remain stable.
To determine the possible size of this partition, in Hard Disk Sentinel please simply move the mouse on the disk surface map (where you saw the darker green blocks). On the bottom status line, you can check the proper location in both sector numbers and MB units. So if you create a partition, just make sure that it should be smaller, to not reach this problematic area.
For example, if the first darker green block is at 3520000 MB, then you can create a partition with size 3500000 MB.
This way you may lose some capacity - but then the drive may remain stable.

However, personally (considering the current low health) I may not feel safe to use hard disk for storing important data.


> I haven't done the Reinitialize test as it requires some 350+ hours.

This sounds really too much. Maybe the hard disk can't operate with full speed? Is it connected to USB 2.0 channel or USB 2.0 adapter/enclosure? That may dramatically reduce performance of a such hard disk.

If you use Report menu -> Send test report to developer option, I'd be happy to check the complete status of the hard disk drive.
This may give additional thoughts, ideas about how to improve the situation in all possible ways.

[Zafar Iqbal]

Thanks for the detailed reply.

When I did the isolated tests, a write test would take 40 minutes for around 40 blocks, but I restarted the computer some hours after writing here and did some tests again. The times dropped to 5-6 minutes and no further reallocated sectors has been reported. I repeated the tests few more time with same results.

Since then I've also done a complete Write test and still no new reallocated sectors has appeared. I'm not sure what the speed/time difference is all about. I installed SeaTools, but never got it working. It would never pass the initialization/startup pass.

The HDD is internal, connected directly to the motherboard - I also have 4 other harddrives.

[hdsentinel]

The estimated test time is based on the performance (speed) of the blocks already tested.
If the software finds problematic, very slow blocks, then yes, the estimated time can be higher - but then it can decrease when the normal performance reached.

This sounds good: this would confirm that after the write test (which was slower) the hard disk could finish reallocations of sectors.
if further, repeated tests show no further reallocations and the tests completed faster, it means that now (when the original sectors no longer used, but the spare sectors used instead) the status seems stable and now you may use the hard disk.

However, considering the lower health and the amount of reallocated sectors, I'd do only with constant monitoring and immediate backup upon on any
(even minor) new issue. Hopefully there will be no further reallocations, but with time, there is higher chance for that.

[Zafar Iqbal]

I'll do few more tests and if there is still no new reallocated sectors showing up, then I think I'm ready to repartitions and use the drive again, but with data of lesser importance.

Thanks again for your time.

[kinjo]

i'm looking for a new 4TB HDD,
can anyone help me to find the best one?

[hdsentinel]

This depends on the actual situation, how do you prefer to use and for what purpose?

For example:
- do you prefer to have an internal hard disk or external removable drive
- do you prefer to store backup data only or actively use,
- do you prefer to store many smaller or fewer bigger files mostly
etc.

For internal, active use, with WD RED series the experiences are usually positive, personally I'd select a 4 TB model from that.
If you look for a 2.5" removable drive, the new Maxtor M3 4 TB model is a good choice: generally it is a Seagate portable drive just its price is more economic.