bad sectors on a mybook WD usb drive
in [Storage]
|
Prev: mysterious discrepancy in the reported free space on two identicalusb drives
Next: mysterious discrepancy in the reported free space on two identicalusb drives
From: Arno on 19 Feb 2010 09:37 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 -- Arno Wagner, Dr. sc. techn., Dipl. Inform., CISSP -- Email: arno(a)wagner.name GnuPG: ID: 1E25338F FP: 0C30 5782 9D93 F785 E79C 0296 797F 6B50 1E25 338F ---- Cuddly UI's are the manifestation of wishful thinking. -- Dylan Evans
From: Bob on 19 Feb 2010 11:34 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. >> 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.) -- Bob Nichols AT comcast.net I am "RNichols42"
From: Rod Speed on 19 Feb 2010 13:02 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. >>>>>> (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. 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.
From: Rod Speed on 19 Feb 2010 13:10 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.
From: Arno on 19 Feb 2010 13:20
Bob <SEE_SIGNATURE(a)localhost.localdomain.invalid> 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. Indeed. It is possible that the WD20EARS uses a different raw temperature format than other WD drives. I have a WD10EAVS, a WD15EADS and two WD notebook drives, a WD5000BEVT and a WD3200BEVT, all have the temperature in C in the raw temperature value. Also the "worst" attribute in the screenshot of the OP indicates that the disk was hotter. Add to that the 2% or so accuracy error of the sensor and the disk may have reached > 67C or so. Also note that while the disk may be operated up to 60C, it will still age much faster. The typical 5 years component lifetime is usually specified at 25C and halves every 10C or so. At 65C the drive has a component life of 4 months, after which its MTBF becomes unspecified. This does not mean the drive will necessarily die. It typically becomes a lot more likely though. >>> 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.) Interesting! Arno -- Arno Wagner, Dr. sc. techn., Dipl. Inform., CISSP -- Email: arno(a)wagner.name GnuPG: ID: 1E25338F FP: 0C30 5782 9D93 F785 E79C 0296 797F 6B50 1E25 338F ---- Cuddly UI's are the manifestation of wishful thinking. -- Dylan Evans |