Need help with "reallocated sector count"?
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From: kimiraikkonen on 15 Nov 2007 09:51 Most of the computer users, including professionals, don't look at or take care SMART's "reallocated sectors count" value, they usually take care full / surface scans against data loss unless SMART reaches to a critical level with alerting. I have e-mailed Seagate to ask about the topic title, they haven't replied with a satisfactory answer so far. Maybe they know or not. Who knows? Even sometimes, i hear contact noise, i detailed it them, they said: if the drive passes long test, i shouldn't worry. As i'm not an amateur, i usually watch SMART values to see what goes on. My other SMART values are those (latest): Are they any value that should make me concerned? (no pending or uncorrectable sectors) Attribute Name Threshold Value Worst Raw value ------------------------------------------------------------------------------------------------------------------ 1 (01) Raw Read Error Rate 34 63 53 2778681 3 (03) Spin Up Time 0 70 70 0 4 (04) Start/Stop Count 20 100 100 692 5 (05) Reallocated Sectors Count 36 98 98 98 7 (07) Seek Error Rate 30 81 60 158998323 9 (09) Power-On Hours 0 93 93 6591 10 (0A) Spin Retry Count 97 100 100 0 12 (0C) Device Power Cycle Count 20 98 98 2602 194 (C2) Temperature 0 21 51 21 195 (C3) Hardware ECC recovered 0 61 53 2778681 197 (C5) Current Pending Sector Count 0 100 100 0 198 (C6) Uncorrectable Sector Count 0 100 100 0 199 (C7) UltraDMA CRC Error Count 0 200 200 0 200 (C8) Write Error Rate (Multi Zone Error Rate) 0 100 253 0 202 (CA) Data Address Mark Errors 0 100 253 0 Sorry, if the lines slide out of the page, i use Google to access newsgroups, don't know how you get here :-( Thanks.
From: Rod Speed on 15 Nov 2007 14:02 kimiraikkonen <kimiraikkonen85(a)gmail.com> wrote: > Most of the computer users, including professionals, don't > look at or take care SMART's "reallocated sectors count" > value, they usually take care full / surface scans against data > loss unless SMART reaches to a critical level with alerting. Anyone who does it like that aint a 'professional'. The MUCH more viable approach is to monitor the raw SMART data over time and consider what changes mean. > I have e-mailed Seagate to ask about the topic title, they haven't replied > with a satisfactory answer so far. Maybe they know or not. Who knows? Its more likely that they just gave up on your rather fractured english. > Even sometimes, i hear contact noise, i detailed it them, they said: And this is a good example of rather fractured english where it isnt at all clear what you are trying to say. > if the drive passes long test, i shouldn't worry. Thats rather superficial advice, because it wont pick up increasing numbers of reallocated sectors which is certainly an indication that the drive is dying. > As i'm not an amateur, i usually watch SMART values to see what goes on. > My other SMART values are those (latest): > Are they any value that should make me concerned? (no pending or uncorrectable sectors) No, the other values are fine given that its a seagate drive. Seagate drives do have those rather high seek error rate and hardware ECC recovered numbers. > Attribute Name Threshold Value > Worst Raw value > ------------------------------------------------------------------------------------------------------------------ > 1 (01) Raw Read Error Rate 34 63 > 53 2778681 > 3 (03) Spin Up Time 0 > 70 70 0 > 4 (04) Start/Stop Count 20 > 100 100 692 > 5 (05) Reallocated Sectors Count 36 98 > 98 98 > 7 (07) Seek Error Rate 30 > 81 60 158998323 > 9 (09) Power-On Hours 0 > 93 93 6591 > 10 (0A) Spin Retry Count 97 100 > 100 0 > 12 (0C) Device Power Cycle Count 20 98 > 98 2602 > 194 (C2) Temperature 0 > 21 51 21 > 195 (C3) Hardware ECC recovered 0 61 > 53 2778681 > 197 (C5) Current Pending Sector Count 0 100 > 100 0 > 198 (C6) Uncorrectable Sector Count 0 100 > 100 0 > 199 (C7) UltraDMA CRC Error Count 0 200 > 200 0 > 200 (C8) Write Error Rate (Multi Zone Error Rate) 0 100 > 253 0 > 202 (CA) Data Address Mark Errors 0 100 > 253 0 > Sorry, if the lines slide out of the page, The correct terminology is wrap. > i use Google to access newsgroups, don't know how you get here :-( You can see that from the post headers.
From: Folkert Rienstra on 15 Nov 2007 14:22 Rod Speed wrote in news:5q15o5Ftnqd3U1(a)mid.individual.net > Franc Zabkar <fzabkar(a)iinternode.on.net> wrote: > > On 13 Nov 2007 07:34:38 GMT, Arno Wagner <me(a)privacy.net> put finger > > to keyboard and composed: > > > > > I once had a Maxtor (in a cluster of compute servers) > > > that was incredible slow and has about 1100 reallocated sectors. > > > This thing was dying pretty fast (had been dropped and it > > > took some weeks to develop problems). The thing was that the > > > SMART status still read good, i.e. above the threshold. > > > At that time I started monitoring the raw reallocated sector > > > count and installed email notification on changes of that.. > > > > > > Some vendors are extremely optimisticc with regard to SMART > > > thresholds. Kind of makes the SMART status alone pretty > > > worthless. No wonder so many people are asking in this group > > > for help interpreting SMART data. > > > > > > Arno > > > > I retired my drive after it started growing bad sectors on a daily > > basis. The last bad sector couldn't be reallocated and showed up as an > > unreadable software file. Sure the drive could have been "fixed" by > > replacing the file and allowing SMART to reallocate the affected > > sector, but I didn't want to have to do this on a regular basis. So I > > can understand why some people replace a drive at the first hint of > > trouble. > > > > Twenty years ago I was servicing the old Control Data storage module > > drives with removable disc packs. If you started to see read errors, > > you could clean the disc heads with alcohol to remove any oxide > > buildup on the head pads. This contamination was the result of minor > > head-to-disc contact and affected the aerodynamics of the head. Once > > you started to see this problem, then you could very quickly end up > > with a head crash. > And modern hard drives dont have the particular problem. Nonsense.
From: Folkert Rienstra on 15 Nov 2007 14:27 Franc Zabkar wrote in news:ngnmj3hj045n52gduimpua7spfjn5p97mf(a)4ax.com > On Wed, 14 Nov 2007 09:23:45 -0800, kimiraikkonen > <kimiraikkonen85(a)gmail.com> put finger to keyboard and composed: > > > On Nov 14, 12:55 pm, Arno Wagner <m...(a)privacy.net> wrote: > > > Previously kimiraikkonen <kimiraikkone...(a)gmail.com> wrote: > > > > Arno, Rod (no quatiton mark :-) ), Franc, > > > > Thanks you for following this topic and keeping replying. > > > > So, as overall when you looked at SMART values, i want to summarize > > > > what i got in that topic? > > > > 1- There are 98 reallocated bad sectors but there's no unallocated as > > > > a threat of data loss? Right? > > > > > > The 98 sectors have been moved out of the way. Not risk from them. > > > > So, they were containing data before they've got reallocated. Right? > > Probably, although you could have encountered some bad sectors from an > unused portion of the disc by running Scandisk with a thorough surface > scan. > > <snip> > > > How much sector will my drive be allowed to reallocate? (eg: What > > about for a modern 40gb drive ? ) > > I posted some stats for my 13GB Seagate HD. If my assumptions are > correct, then each percentage point reflects a loss of approximately > 40 sectors. In my case that means that my drive can reallocate 2560 > sectors before it drops below the threshold, after which it should > return a bad SMART status. > > If I were you I would backup and retire your drive. Once it starts to > develop bad sectors, then the numbers can only grow. You need to ask > yourself how important your data are. > > > That's why the full / surface scan utilities are there. They report > > "bad" , really "bad" sectors which can't be allocated by firmware of > > HDD. Right? > > AFAIK, all bad sectors can be reallocated, if enough spares are > available. The problem in this particular case is that the drive will > not reallocate an uncorrectable bad sector until it is sure that the > OS no longer wants the data contained within it. The way that the OS > signals that the data in this sector are no longer of any consequence > is by writing to it. As soon as the drive is asked to write to this > bad sector, > it reallocates a spare and writes the new data to it instead. Not necessarily, it may reuse the same sector. > > In my case I have had a "pending" sector for almost the entire life of > the drive. This is because I ran Scandisk with a thorough surface scan > after FDISKing and formatting my drive. Scandisk found one bad sector > and marked is as such in the FAT. Hence the OS has avoided writing to > it ever since and the "pending" status has remained. > > - Franc Zabkar
From: Folkert Rienstra on 15 Nov 2007 15:43
Arno Wagner wrote in news:5q1j4gFtblivU3(a)mid.individual.net > Previously kimiraikkonen <kimiraikkonen85(a)gmail.com> wrote: > > On Nov 14, 12:55 pm, Arno Wagner <m...(a)privacy.net> wrote: > > > Previously kimiraikkonen <kimiraikkone...(a)gmail.com> wrote: [bigsnip] > > > That's why the full / surface scan utilities are there. They report > > "bad" , really "bad" sectors which can't be allocated by firmware of > > HDD. Right? > > They report bad sectors that were not reallocated yet. > The disk can allways reallocate sectors, Not on reads alone. > but sometimes only with dataloss Nope. > or after several tries. Always, on reads. Even has to cross a limit for that. > > > > > 5- Though a drive has "reallocated sectors", if it can read every data > > > > (checking with several disk reading utilites), it doesn't have a > > > > unallocatable / unfixable bad sectos which are the reasons of real > > > > data loss. > > > > > > The reallocated sectros are recognized _and_ corrected problems. > > > These sectors will not cause problems in the future. Other > > > sectors may go bad, but if a complete surface scan does not > > > show any, all data is in sectors that are fine or at least look > > > like it. In rare cases a sector can work with some data, but be > > > defect with other data. > > > Very rare with today's disks, due to > > > heavy use of error correcting codes. There is always a breaking point somewhere. Otherwise bad sectors would not exist. > > > > > > You still may want to do a complete surface scan regularly, > > > so that the disk can recognize sectors slowly going bad > > > in time and can rescue the data in them. I run such a test > > > every 14 days automatically, but once every 1-2 months should > > > do fine. You can make that a part of your standard backup > > > procedure. > > > I usually do it if i record important data. But still "none" bad > > sectors have been reported by surface scan of Seatools. > > > So, can i say i don't have any bad sectors present at the moment? > No. Yes. > But if you have bad sectors, they cannot be detected by a read only test. Babblebot, utterly clueless as always. > And the probability of such sectors is pretty small. > > Arno |