bad sectors on a mybook WD usb drive
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From: Rod Speed on 19 Feb 2010 13:20 sobriquet wrote > Arno <m...(a)privacy.net> wrote >> sobriquet <dohduh...(a)yahoo.com> wrote >>> Rod Speed <rod.speed....(a)gmail.com> wrote >>>> sobriquet wrote >>>>> I've lost some data on a 2 tb WD mybook usb drive. When >>>>> I did a full scan, it found something like 3 mb in bad sectors. >> I assume that is 3 MB (which is 8'000'000'000 times more, >> "mb" is milli-bit, you want Mega-Byte). That is a lot. > Millibit would make sense in this discussion (since computers don't > deal with fractional bits), so obviously mb means megabyte, like tb > means terrabyte. I'm sloppy with capitals sometimes, sorry. > I thought 3 MB was not really that much in proportion to the total > size of the drive (2 TB = 2 * 1024 * 1024 MB = 2097152 MB) What matters is the number of sectors affected. Turns out its only 6 and thats not too bad given the utterly obscene temperature the drive peaked at, 87C. >>>>> However, when I reformatted the drive, somehow all bad sectors were >>>>> recovered. Apparently, there is some redundancy in diskspace, so it >>>>> can allocate some of that extra space to substitute for the bad >>>>> sectors on disk when it's just a small section of bad sectors. >>>> Yes, all modern hard drives have spare sectors >>>> that can be used as substitutes for bad sectors. >>>>> The disk is also able to pass the short drive test (in winDLG >>>>> under xp), that it used to fail, before I reformatted the drive. >> That is also normal. This "recovery" is only useful >> if the defects are not the fault of the drive. >>>>> Now I wonder if the fact that previously bad sectors have occurred and >>>>> I've lost data, is that increasing the likelyhood that this might happen again? >>>> Yes, that many bad sectors does indicate a problem with >>>> the drive or that the drive is running much too hot etc. >>>>> Is the drive less reliable in any way once a small >>>>> number of bad sectors have been identified >> Not necessarily. It depends on the reason. If it is the drives >> own fault, about 10 or more bad sectors are pretty bad. >> If it is extern influence (vibration, bad PSU,...) even >> a very, very large number like yours does not necessary >> say the drive is unreliable after (!) the external problem >> has been corrected. > How much redundant space does a typical 2 TB drive have to replace bad sectors? Varys with the drive, but a hell of a lot more than the 6 you have a problem with. But what matters is that if you have more than a few due to the drive itself and not something external to the drive like vibration etc, then its evidence that the drive is dying long before you use up all the spares. You can get occassional bads due to mains failures with some drives that dont handle loss off power that well, but that really the only situation where a small number of bad sectors is acceptible. With everything else, its always an indication that the drive is dying if the problem isnt external to the drive. In your case the drive got absolutely stinking hot at 87C max and thats what produced the bad sectors. If you can stop it getting anything like that hot again, the drive should be fine life wise. Not that easy to do tho with an external drive with poor cooling of the drive. > The drive was in operation on an uneven surface and > perhaps it moved around or bumped slightly during operation. Nar, its definitely the grossly excessive temperature that was the problem. Interesting that the stupid WDdlg didnt even mention any problem. Utterly obscene, actually. > I hope solid state disks will become more affordable > soon, as they seem more resilient to minor shocks. Yes, but your problem was not minor shocks. >>>> Yes, and 3MB is not a small number of bad sectors. >>>>> (even though the bad sectors are no longer visible after the >>>>> drive has been formatted again and other drivespace is >>>>> substituted for the bad sectors)? >>>> Yes, it either indicates that the drive is dying, or that its running stinking hot etc. >>>>> ?Below is the original log from chdsk when the bad sectors were found: >>>> chkdsk isnt a very useful indication of the health of the drive. >>>> You really need a proper SMART report on the drive. >>>> That isnt necessarily that easy to get for free with an external drive. >>> Well, with winDLG, it does say the SMART status is OK for the >>> device, and I can get more detailed SMART info. >> The "smart status" is over-optimistic in most cases. >>> Here is a screenshot of the SMART info: >>> http://img11.imageshack.us/img11/74/wdmybook.jpg >> It is hard to say anything from this, as the raw values >> are missing. It looks as the defects were actually not >> replaced but really recoverd (attribute 5 is still >> at value 200) and nothing else is suspicuous. >> This looks like the sectors are fine, but something >> interferred with the write operation. > I have another screenshot that also shows the raw values. > http://img713.imageshack.us/img713/5343/everestje.jpg >> How have you handled the drive? Moved it around >> or bumped it during operation? Used it with not too >> clean power? Used it on a surface that vibrated or >> was otherwise mechanically unstable? > Well, in a typical situation, I might have the drive on the desk and > then being somewhat absent minded, I might be drumming along > with some music with my hands on the desk a bit too enthusiastically, > which might make the disk vibrate too much. > I dunno how sensitive these drives are and how much of a shock might > pose a serious problem during reading from or writing to the drive. It should handle that fine, but not say the drive falling over etc.
From: Rod Speed on 19 Feb 2010 13:24 Bob wrote: > Arno wrote: >> sobriquet <dohduhdah(a)yahoo.com> wrote: >>> On 19 feb, 00:15, Arno <m...(a)privacy.net> wrote: >> >>> I have another screenshot that also shows the raw values. >> >>> http://img713.imageshack.us/img713/5343/everestje.jpg >> >> Except for the temperature, the drive looks perfectly >> healty. The temperature is 63C (if the encoding is >> the same as on other WD drives) and 63C is deep >> into HDD killer territory. More than 50C is reason >> for real concern and typically above the maximum >> allowed temperature. From 65-75C or so, the mechanics >> and electronics starts to fail (non-permanently, but >> ageing very fast, like beging dead from old age within >> weeks-months), so that is possibly were your >> defects came from: You got the disk so hot it >> stopped working right. >> >> You need to bring donwn the temperature. > > Amen. The WD20EARS has a 60C spec for maximum operating temperature. > It's hard to imagine what WD did to get that very low power drive > (6.0 Watts read/write, 3.7 Watts idle) to heat up that much in that > external enclosure. In fact the Everest SMART report shows that it actually got to 87C and that is utterly obscene. >>> Well, in a typical situation, I might have the drive on the desk and >>> then being somewhat absent minded, I might be drumming along with >>> some music with my hands on the desk a bit too enthusiastically, >>> which might make the disk vibrate too much. >>> I dunno how sensitive these drives are and how much of a shock might >>> pose a serious problem during reading from or writing to the drive. >> >> Maybe. Lound sounds can cause problems. Here is an >> enlightening video demonstrating the effect: >> >> http://www.youtube.com/watch?v=tDacjrSCeq4 >> >> This can also cause write defects, were the data is >> unreadable (i.e. you have data loss) but the sector is again >> fine after an overwrite. > > My lesson in vibration effects came when I had a very bad tape drive > that I was using one final time to recover data from some old > DC600-style tapes. A bad roller was causing a lot of vibration, and > to stop a spew of disk errors I had to pull the tape drive out of the > housing it shared with the disk drives. (Recovered the data -- > junked the tape drive and tapes.)
From: sobriquet on 19 Feb 2010 16:29 On 19 feb, 19:10, "Rod Speed" <rod.speed....(a)gmail.com> wrote: > Rod Speed wrote > > > > > > > sobriquet wrote > >> sobriquet <dohduh...(a)yahoo.com> wrote > >>> Rod Speed <rod.speed....(a)gmail.com> wrote > >>>> sobriquet wrote > >>>>> Rod Speed <rod.speed....(a)gmail.com> wrote > >>>>>> sobriquet wrote > >>>>>>> I've lost some data on a 2 tb WD mybook usb drive. When > >>>>>>> I did a full scan, it found something like 3 mb in bad sectors. > >>>>>>> However, when I reformatted the drive, somehow all bad sectors > >>>>>>> were recovered. Apparently, there is some redundancy in diskspace, so it can allocate some of that extra space > >>>>>>> to substitute for the bad sectors on disk when it's just a small section of bad sectors. > >>>>>> Yes, all modern hard drives have spare sectors > >>>>>> that can be used as substitutes for bad sectors. > >>>>>>> The disk is also able to pass the short drive test (in winDLG > >>>>>>> under xp), that it used to fail, before I reformatted the drive. > >>>>>>> Now I wonder if the fact that previously bad sectors have occurred and I've lost data, is that increasing the > >>>>>>> likelyhood that this > >>>>>>> might happen again? > >>>>>> Yes, that many bad sectors > > It isnt in fact all that many now that we can see the SMART data. > >>>>>> does indicate a problem with the drive or > >>>>>> that the drive is running much too hot etc. > >>>>>>> Is the drive less reliable in any way once a small > >>>>>>> number of bad sectors have been identified > >>>>>> Yes, and 3MB is not a small number of bad sectors. > > Turns out to only be 3 bad sectors. > > And 3 more pending. > > > > > > >>>>>>> (even though the bad sectors are no longer visible after the > >>>>>>> drive has been formatted again and other drivespace is > >>>>>>> substituted for the bad sectors)? > >>>>>> Yes, it either indicates that the drive is dying, or that its > >>>>>> running stinking hot etc. > >>>>>>> Below is the original log from chdsk when the bad sectors were found: > >>>>>> chkdsk isnt a very useful indication of the health of the drive. > >>>>>> You really need a proper SMART report on the drive. > >>>>>> That isnt necessarily that easy to get for free with an external drive. > >>>>> Well, with winDLG, it does say the SMART status is OK for the device, > >>>> That never means much, its the detailled values that matter. > >>>>> and I can get more detailed SMART info. > >>>>> Here is a screenshot of the SMART info: > >>>>>http://img11.imageshack.us/img11/74/wdmybook.jpg > >>>> It isnt at all clear what that actually means, particularly what the warranty field means. > >>>> And the reallocated sector entry and the temperature entry make no sense either. > >>>> The Everest SMART report is much more readable, > >>>> but doesnt work with external drives in the free version. > >>>> smartclt from a linux bootable cd might, and HDSentinal might, but it isnt free. > >>> The version I've tried from HDSentinel wasn't up to date, but perhaps the version (5.30) of Everest on demonoid will > >>> provide more detailed > >>> SMART info on the drive. I'm busy with the drive now, but I'll soon > >>> follow up on this with a screenshot of the Everest SMART info of > >>> the drive. > >> Screenshot of Everest SMART info of the same drive: > >>http://img713.imageshack.us/img713/5343/everestje.jpg > > Thats much better. That shows 3 reallocated sectors which > > isnt too bad given the utterly obscene temperature of 63C. > > And its actually been to 87, thats completely and utterly obscene. > > > The temperature is certainly the problem and the > > drive will be fine if you can stop it getting that hot. > > Not easy to stop it getting that hot tho, particularly in the > > summer without air conditioning etc with those external drives. > > I'd be returning it if it was mine, but that wouldnt be a warranty claim and how > easy it would be to do that depends on your country and its consumer laws. > > The technical term is unfit for purpose in countrys with a legal system derived from the british system. > > I cant remember the detail with Dutch law. http://img62.imageshack.us/img62/5758/everest1q.jpg So that means one of my internal hitachi drives reached a temperature of 150C?!
From: Franc Zabkar on 19 Feb 2010 18:12 On 19 Feb 2010 14:37:00 GMT, Arno <me(a)privacy.net> put finger to keyboard and composed: >Franc Zabkar <fzabkar(a)iinternode.on.net> wrote: >> On Thu, 18 Feb 2010 12:43:25 -0800 (PST), sobriquet >> <dohduhdah(a)yahoo.com> put finger to keyboard and composed: > >>>Here is a screenshot of the SMART info: >>>http://img11.imageshack.us/img11/74/wdmybook.jpg > >> IIUC, WD's temperature attribute assigns a normalised value of 100 to >> a temperature of 50C. A value of 89 would then suggest that the >> temperature is 61C. > >> I could be wrong, though ... > >With the WDs I have the raw attribute seems to be C directly. > >Arno I was referring to the normalised attribute value. Wikipedia is unclear, but it does mention something along those lines for attribute BE: http://en.wikipedia.org/wiki/S.M.A.R.T. - Franc Zabkar -- Please remove one 'i' from my address when replying by email.
From: Rod Speed on 19 Feb 2010 22:00
sobriquet wrote: > On 19 feb, 19:10, "Rod Speed" <rod.speed....(a)gmail.com> wrote: >> Rod Speed wrote >> >> >> >> >> >>> sobriquet wrote >>>> sobriquet <dohduh...(a)yahoo.com> wrote >>>>> Rod Speed <rod.speed....(a)gmail.com> wrote >>>>>> sobriquet wrote >>>>>>> Rod Speed <rod.speed....(a)gmail.com> wrote >>>>>>>> sobriquet wrote >>>>>>>>> I've lost some data on a 2 tb WD mybook usb drive. When >>>>>>>>> I did a full scan, it found something like 3 mb in bad >>>>>>>>> sectors. >>>>>>>>> However, when I reformatted the drive, somehow all bad sectors >>>>>>>>> were recovered. Apparently, there is some redundancy in >>>>>>>>> diskspace, so it can allocate some of that extra space to >>>>>>>>> substitute for the bad sectors on disk when it's just a small >>>>>>>>> section of bad sectors. >>>>>>>> Yes, all modern hard drives have spare sectors >>>>>>>> that can be used as substitutes for bad sectors. >>>>>>>>> The disk is also able to pass the short drive test (in winDLG >>>>>>>>> under xp), that it used to fail, before I reformatted the >>>>>>>>> drive. >>>>>>>>> Now I wonder if the fact that previously bad sectors have >>>>>>>>> occurred and I've lost data, is that increasing the >>>>>>>>> likelyhood that this >>>>>>>>> might happen again? >>>>>>>> Yes, that many bad sectors >>> It isnt in fact all that many now that we can see the SMART data. >>>>>>>> does indicate a problem with the drive or >>>>>>>> that the drive is running much too hot etc. >>>>>>>>> Is the drive less reliable in any way once a small >>>>>>>>> number of bad sectors have been identified >>>>>>>> Yes, and 3MB is not a small number of bad sectors. >>> Turns out to only be 3 bad sectors. >> >> And 3 more pending. >> >> >> >> >> >>>>>>>>> (even though the bad sectors are no longer visible after the >>>>>>>>> drive has been formatted again and other drivespace is >>>>>>>>> substituted for the bad sectors)? >>>>>>>> Yes, it either indicates that the drive is dying, or that its >>>>>>>> running stinking hot etc. >>>>>>>>> Below is the original log from chdsk when the bad sectors >>>>>>>>> were found: >>>>>>>> chkdsk isnt a very useful indication of the health of the >>>>>>>> drive. >>>>>>>> You really need a proper SMART report on the drive. >>>>>>>> That isnt necessarily that easy to get for free with an >>>>>>>> external drive. >>>>>>> Well, with winDLG, it does say the SMART status is OK for the >>>>>>> device, >>>>>> That never means much, its the detailled values that matter. >>>>>>> and I can get more detailed SMART info. >>>>>>> Here is a screenshot of the SMART info: >>>>>>> http://img11.imageshack.us/img11/74/wdmybook.jpg >>>>>> It isnt at all clear what that actually means, particularly what >>>>>> the warranty field means. And the reallocated sector entry and >>>>>> the temperature entry make no sense either. >>>>>> The Everest SMART report is much more readable, >>>>>> but doesnt work with external drives in the free version. >>>>>> smartclt from a linux bootable cd might, and HDSentinal might, >>>>>> but it isnt free. >>>>> The version I've tried from HDSentinel wasn't up to date, but >>>>> perhaps the version (5.30) of Everest on demonoid will provide >>>>> more detailed >>>>> SMART info on the drive. I'm busy with the drive now, but I'll >>>>> soon >>>>> follow up on this with a screenshot of the Everest SMART info of >>>>> the drive. >>>> Screenshot of Everest SMART info of the same drive: >>>> http://img713.imageshack.us/img713/5343/everestje.jpg >>> Thats much better. That shows 3 reallocated sectors which >>> isnt too bad given the utterly obscene temperature of 63C. >> >> And its actually been to 87, thats completely and utterly obscene. >> >>> The temperature is certainly the problem and the >>> drive will be fine if you can stop it getting that hot. >>> Not easy to stop it getting that hot tho, particularly in the >>> summer without air conditioning etc with those external drives. >> >> I'd be returning it if it was mine, but that wouldnt be a warranty >> claim and how >> easy it would be to do that depends on your country and its consumer >> laws. >> >> The technical term is unfit for purpose in countrys with a legal >> system derived from the british system. >> >> I cant remember the detail with Dutch law. > > http://img62.imageshack.us/img62/5758/everest1q.jpg > > So that means one of my internal hitachi drives reached a temperature of 150C?! Nope, 40C |