Is my HDD failing as SMART parameter (Reallocated Sector count) is very high(390K)

3

I have a 2 year old 500GB HGST 5400rpm laptop HDD. I started tracking its SMART parameters a while ago, and number of Reallocated sectors(in decimal) has increased from 65k in Nov,2015 to 393264 in May,2016.Refer to the link below to view the history of the this parameter.

History of Reallocated sectors

My HDD is working fine but I am really worried that it may one day unexpectedly fail due to increasing number of Reallocated sectors.Should I be worried?

SMART parameters screenshot

Tanuj Sharma

Posted 2016-05-22T12:51:57.060

Reputation: 33

1Reallocated sectors can be an indication of a failing drive, although I have a 5 year old HGST drive that a blip of this over this three years ago and not a thing since. Perhaps you could post the entire SMART diagnostic output? – acejavelin – 2016-05-22T13:06:30.373

The question is - how many do you have left? Certain SMART parameters have a threshold value. The initial value should also be known. So if you started with 100 and you are at 90 and the threshold is 50, you have used 20% of the repair capabilities that the manufacturer considers in the safe range, but only 10% of the total repair capability. I am quite surprised about the numbers though - reallocated sectors on the disk I checked are 0 and occasionnaly one or two; Possibly HGST has a different approach. – le_top – 2016-05-22T21:20:40.390

@acejavelin I have added a screenshot. Let me know if more info is required. – Tanuj Sharma – 2016-05-24T17:47:51.263

FWIW, a HDD of mine recently failed after it had exceeded 448+ reallocated sectors (a steady increase over 6 months). I assume "390k" must be the number of bytes, rather than the number of "sectors"?! (1 sector = 512 or 4096 bytes ...?) – MrWhite – 2016-05-30T01:26:19.247

Well the SMART parameter says "Reallocated sectors" but i really don't know.... – Tanuj Sharma – 2016-06-02T08:21:28.543

BTW, now there are 460k reallocated sectors. – Tanuj Sharma – 2016-06-02T08:22:14.783

Answers

6

Short answer: Backup your data and replace the drive as soon as possible, it is failing

Long answer: Yes, you should be worried... The drive is failing, it may die as your reading this, or it could go for months or years, but it is failing. 393k sectors is very excessive and the fact it is increasing means the drive is continuing to degrade. Acronis has a knowledge base article explaining what it is, or from Wikipedia's S.M.A.R.T. entry page:

Reallocated Sector Count
Better: lower
Severity: Critical

Count of reallocated sectors. When the hard drive finds a read/write/verification error, it marks that sector as "reallocated" and transfers data to a special reserved area (spare area). This process is also known as remapping, and reallocated sectors are called "remaps". The raw value normally represents a count of the bad sectors that have been found and remapped. Thus, the higher the attribute value, the more sectors the drive has had to reallocate. This allows a drive with bad sectors to continue operation; however, a drive which has had any reallocations at all is significantly more likely to fail in the near future.[3] While primarily used as a metric of the life expectancy of the drive, this number also affects performance. As the count of reallocated sectors increases, the read/write speed tends to become worse because the drive head is forced to seek to the reserved area whenever a remap is accessed. If sequential access speed is critical, the remapped sectors can be manually marked as bad blocks in the file system in order to prevent their use.

Seeing this parameter at a near zero value is normal, provided it does not increase over time, because that is an indication of degrading hardware and potential imminent failure. Regardless of the results of any self-testing or other information, this drive should be replaced as soon as possible to prevent catastrophic data loss.

Personally, if this value in excess of ~20 (not 20k or 200k, but 20) or an increasing value, I implement backup and hardware replacement procedures as soon as possible.

A quick check of a few drives on some computers on our test bench indicate all have their values for Reallocated Sector Count are 0, except one laptop which shows a value of 8, but it's 2 year history indicates only one reallocation event about 15 months ago.

acejavelin

Posted 2016-05-22T12:51:57.060

Reputation: 5 341

Thanks for the answer. I have already backed up my data and I may actually get a new laptop and give this one to my parents. – Tanuj Sharma – 2016-05-25T05:27:00.600