Recently I bought a second hand HD which I immediately tested by running the drive reinitialization with default values. The test was successful, no bad sectors or any warnings.
Some days after installing the drive, I saw that the health of the drive went down. This was due to the current pending sector count. I checked the cables etc. and reran reinitialization and the count went to zero. However, at this point, the reallocation event count also rose when the drive was processing the weak sector areas but the actual reallocated sectors count didn't. I tried a regular Windows format operation but it also only made the reallocation event count rise but no sectors were reallocated.
Currently the count shows 99 but still there are no reallocated sectors according to the data. How is this possible, does it mean that there are actually no spare areas at all? Is it actually more likely that there is some other problem than the drive failing since the pending sectors count is not constant?
Thanks for any thoughts.
Reallocation event count vs. realloc sectors count
-
hdsentinel
- Site Admin
- Posts: 3128
- Joined: 2008.07.27. 17:00
- Location: Hungary
- Contact:
Re: Reallocation event count vs. realloc sectors count
On a new hard disk, there should be free spare area for reallocation, so it should not be problem. If the drive would report high number of bad (reallocated) sectors, then it is possible that the spare area is full - but on a new drive it is not possible.
The reallocation event count increases in all attempts when the drive starts the reallocation procedure. This includes all attempts when the reallocation does not complete because of a device error or when the drive finds that the reallocation is not required as the sector currently seems usable. I mean that during the reallocation the drive tries to copy all data from the problematic sector to the spare area (usually by special methods and by slower speed) and it is possible that during this, the sector seems perfect - and the drive cancels the reallocation.
However yes, the corresponding sector may be damaged from time to time and if this happens, it may result in
- lower performance when accessing the sector (as the drive may periodically try the reallocation)
- damaged file(s) / file system if the sector goes to the pending (weak) state
Yes, the Reinitialise Disk Surface test in most cases forces the drive to reallocate the corresponding sector - but some drives may not perform the reallocation this way.
Some time ago I experienced similar on a 500 GB Hitachi drive. The Disk menu -> Surface test -> Read test showed that the 3rd block was much slower than expected (the surface map always showed a darker green block there, regardless of how many times the test started). Accessing (for both reading / writing) increased the reallocation even count value - but no sectors were actually reallocated, even when the Reinitialise Disk Surface Test started (and targeted only that particular block) 100 times.
The best solution was to create a small partition (500 MB) on the beginning of the drive (which contained the problematic area), then create a big partition for the actual, good data area and then removing the first small partition. This way during normal use the drive never accessed those problematic sectors and (by losing 0.1 % capacity) I could make the drive working without problems, without further issues and degradations in the health, there are no file/file system damages and so. The drive is still working after years of this.
Not sure, but if your drive reports the problem (maybe slowness by Disk menu -> Surface test -> Read test) on the same block (even after you re-run the test), and it is in the beginning / end of the drive surface area, such solution can help.
Ps. it may be interesting to check the actual situation (complete S.M.A.R.T. information) of this drive in this special case, so please use Report menu -> Send test report to developer option.
You may use it many times, for example now and later if you perform some testing / using of the drive, so then it is possible to check any changes.
The reallocation event count increases in all attempts when the drive starts the reallocation procedure. This includes all attempts when the reallocation does not complete because of a device error or when the drive finds that the reallocation is not required as the sector currently seems usable. I mean that during the reallocation the drive tries to copy all data from the problematic sector to the spare area (usually by special methods and by slower speed) and it is possible that during this, the sector seems perfect - and the drive cancels the reallocation.
However yes, the corresponding sector may be damaged from time to time and if this happens, it may result in
- lower performance when accessing the sector (as the drive may periodically try the reallocation)
- damaged file(s) / file system if the sector goes to the pending (weak) state
Yes, the Reinitialise Disk Surface test in most cases forces the drive to reallocate the corresponding sector - but some drives may not perform the reallocation this way.
Some time ago I experienced similar on a 500 GB Hitachi drive. The Disk menu -> Surface test -> Read test showed that the 3rd block was much slower than expected (the surface map always showed a darker green block there, regardless of how many times the test started). Accessing (for both reading / writing) increased the reallocation even count value - but no sectors were actually reallocated, even when the Reinitialise Disk Surface Test started (and targeted only that particular block) 100 times.
The best solution was to create a small partition (500 MB) on the beginning of the drive (which contained the problematic area), then create a big partition for the actual, good data area and then removing the first small partition. This way during normal use the drive never accessed those problematic sectors and (by losing 0.1 % capacity) I could make the drive working without problems, without further issues and degradations in the health, there are no file/file system damages and so. The drive is still working after years of this.
Not sure, but if your drive reports the problem (maybe slowness by Disk menu -> Surface test -> Read test) on the same block (even after you re-run the test), and it is in the beginning / end of the drive surface area, such solution can help.
Ps. it may be interesting to check the actual situation (complete S.M.A.R.T. information) of this drive in this special case, so please use Report menu -> Send test report to developer option.
You may use it many times, for example now and later if you perform some testing / using of the drive, so then it is possible to check any changes.