Need help with "reallocated sector count"?
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From: Folkert Rienstra on 13 Nov 2007 12:31 kimiraikkonen wrote in news:1194948215.644693.131060(a)v3g2000hsg.googlegroups.com > 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? > > > 2-ID Attribute Description Threshold Value Worst Data Status > 05 Reallocated Sector Count 36 98 98 98 OK: Value is normal > > That means there are 98 reallocated sectors, but still couldn't > completely understand for Seagate what "threshold - 36" means? It > shouldn't be percantage, does it mean that i'm allowed to allocate > 100-36 = 64 bad ones? (frustrating) > > 3- The other SMART values are fine as stated by many programs. Right? > > 4- A "reallocated sector count" shows the amount of reallocated / > replaced sectors silently while the drive is operating. When the drive > has a problem with sector, first it tries to replace that sectors with > a "spare" sector thus a "reallocated sector" statistic is updated. > > If the sector is completely unreadable or unreallocatable, you see it > as "bad" marked in surface scan tools like Seatools. Did i understand > correct? > > 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. > > Those 5 questions are the ones i see answered them clearly. > Again, thank you for following and helping. Very helpful... Yeah, pity none of them recognized your original report for what it was and none of them ever called a S.M.A.R.T. report correct. > > Regards.
From: Rod Speed on 13 Nov 2007 14:28 kimiraikkonen <kimiraikkonen85(a)gmail.com> wrote > Arno, Rod (no quatiton mark :-) ), Just as well, the death squad would have got its orders otherwise |-) > 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 english is too fractured there for it to be clear what the last half is asking. > 2-ID Attribute Description Threshold Value Worst Data Status > 05 Reallocated Sector Count 36 98 98 98 OK: Value is normal > That means there are 98 reallocated sectors, Yes. > but still couldn't completely understand for Seagate what "threshold - 36" means? Dont worry about it, those thresholds are too conservative to be useful in this situation. > It shouldn't be percantage, does it mean that i'm allowed > to allocate 100-36 = 64 bad ones? (frustrating) No, it doesnt mean that. > 3- The other SMART values are fine as stated by many programs. Right? Yes, but its the Data value that matters, not what the SMART utes say. > 4- A "reallocated sector count" shows the amount of reallocated / > replaced sectors silently while the drive is operating. Yes, tho it may have needed a deliberate write to the sector to get the drive to reallocate it. The drive wont necessarily reallocate on reads that fail, mainly so you can try hard to get the data out of the sector before its reallocated. > When the drive has a problem with sector, first it tries to replace that sectors > with a "spare" sector thus a "reallocated sector" statistic is updated. Yes, but not necessarily on a read that fails, see above. > If the sector is completely unreadable or unreallocatable, you see it as "bad" > marked in surface scan tools like Seatools. Did i understand correct? No, that can also be just a sector that cant be read but which can be reallocated if you write to it, triggering the drive to do a reallocation. Its done like that so you can try hard to get data out of the sector before its reallocated. > 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. Its more complicated than that with that many reallocated sectors. Thats usually evidence that the drive is dying. Whereas one or two reallocated sectors may be quite acceptible and not evidence that the drive is dying. > Those 5 questions are the ones i see answered them clearly. Thats too fractured to understand too. > Again, thank you for following and helping. Very helpful... Thats what these technical newsgroups are for.
From: kimiraikkonen on 13 Nov 2007 17:55 On Nov 13, 9:28 pm, "Rod Speed" <rod.speed....(a)gmail.com> wrote: > kimiraikkonen <kimiraikkone...(a)gmail.com> wrote > > > Arno, Rod (no quatiton mark :-) ), > > Just as well, the death squad would have got its orders otherwise |-) > > > 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 english is too fractured there for it to be clear what the last half is asking. Then teach me the correct way of explaining, sorry if couldn't put thoughts into words in my mind. > > 2-ID Attribute Description Threshold Value Worst Data Status > > 05 Reallocated Sector Count 36 98 98 98 OK: Value is normal > > That means there are 98 reallocated sectors, > > Yes. > > > but still couldn't completely understand for Seagate what "threshold - 36" means? > > Dont worry about it, those thresholds are too conservative to be useful in this situation. > > > It shouldn't be percantage, does it mean that i'm allowed > > to allocate 100-36 = 64 bad ones? (frustrating) > > No, it doesnt mean that. > > > 3- The other SMART values are fine as stated by many programs. Right? > > Yes, but its the Data value that matters, not what the SMART utes say. > > > 4- A "reallocated sector count" shows the amount of reallocated / > > replaced sectors silently while the drive is operating. > > Yes, tho it may have needed a deliberate write to the sector to get the drive > to reallocate it. The drive wont necessarily reallocate on reads that fail, mainly > so you can try hard to get the data out of the sector before its reallocated. > > > When the drive has a problem with sector, first it tries to replace that sectors > > with a "spare" sector thus a "reallocated sector" statistic is updated. > > Yes, but not necessarily on a read that fails, see above. > > > If the sector is completely unreadable or unreallocatable, you see it as "bad" > > marked in surface scan tools like Seatools. Did i understand correct? > > No, that can also be just a sector that cant be read but which can be > reallocated if you write to it, triggering the drive to do a reallocation. I meant, bad blocks are seen as "bad" in surface scan why they're really bad / unreadable. They cannot be allocated or allocation pool(spare area) has failed / full. Then, when do a user see bad sectors reported after a full / surface scan? > Its done like that so you can try hard to get data out of the sector before its reallocated. Did it but still drive seems OK. > > 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. > > Its more complicated than that with that many reallocated sectors. > > Thats usually evidence that the drive is dying. > > Whereas one or two reallocated sectors may be quite > acceptible and not evidence that the drive is dying. > > > Those 5 questions are the ones i see answered them clearly. > > Thats too fractured to understand too. Again language critisism, sorry if there were due to confusion. > > Again, thank you for following and helping. Very helpful... > > Thats what these technical newsgroups are for. Correct.
From: Rod Speed on 13 Nov 2007 18:57 kimiraikkonen <kimiraikkonen85(a)gmail.com> wrote: > On Nov 13, 9:28 pm, "Rod Speed" <rod.speed....(a)gmail.com> wrote: >> kimiraikkonen <kimiraikkone...(a)gmail.com> wrote >> >>> Arno, Rod (no quatiton mark :-) ), >> >> Just as well, the death squad would have got its orders otherwise |-) >> >>> 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 english is too fractured there for it to be clear what the last half is asking. > Then teach me the correct way of explaining, Not possible unless I can work out what you are trying to say in that last half, and I still cant. > sorry if couldn't put thoughts into words in my mind. >>> 2-ID Attribute Description Threshold Value Worst Data Status >>> 05 Reallocated Sector Count 36 98 98 98 OK: Value is normal >>> That means there are 98 reallocated sectors, >> >> Yes. >> >>> but still couldn't completely understand for Seagate what >>> "threshold - 36" means? >> >> Dont worry about it, those thresholds are too conservative to be >> useful in this situation. >> >>> It shouldn't be percantage, does it mean that i'm allowed >>> to allocate 100-36 = 64 bad ones? (frustrating) >> >> No, it doesnt mean that. >> >>> 3- The other SMART values are fine as stated by many programs. >>> Right? >> >> Yes, but its the Data value that matters, not what the SMART utes >> say. >> >>> 4- A "reallocated sector count" shows the amount of reallocated / >>> replaced sectors silently while the drive is operating. >> >> Yes, tho it may have needed a deliberate write to the sector to get >> the drive >> to reallocate it. The drive wont necessarily reallocate on reads >> that fail, mainly >> so you can try hard to get the data out of the sector before its >> reallocated. >> >>> When the drive has a problem with sector, first it tries to replace >>> that sectors with a "spare" sector thus a "reallocated sector" >>> statistic is updated. >> >> Yes, but not necessarily on a read that fails, see above. >> >>> If the sector is completely unreadable or unreallocatable, you see >>> it as "bad" marked in surface scan tools like Seatools. Did i >>> understand correct? >> >> No, that can also be just a sector that cant be read but which can be >> reallocated if you write to it, triggering the drive to do a reallocation. > I meant, bad blocks are seen as "bad" in surface scan > why they're really bad / unreadable. They cannot be > allocated or allocation pool(spare area) has failed / full. The allocation pool of spare sectors will be empty, not full. > Then, when do a user see bad sectors reported after a full / surface scan? Because that is a read only scan, and the drive wont always reallocate those if it cant read the contents after multiple retrys, so you can use something else to get the data back before its reallocated. >> Its done like that so you can try hard to get >> data out of the sector before its reallocated. > Did it but still drive seems OK. Because the diagnostic has rewritten those bad sectors, because you told it to try 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. >> Its more complicated than that with that many reallocated sectors. >> Thats usually evidence that the drive is dying. >> Whereas one or two reallocated sectors may be quite >> acceptible and not evidence that the drive is dying. >>> Those 5 questions are the ones i see answered them clearly. >> Thats too fractured to understand too. > Again language critisism, sorry if there were due to confusion. >>> Again, thank you for following and helping. Very helpful... >> Thats what these technical newsgroups are for. > Correct.
From: Arno Wagner on 14 Nov 2007 05:55
Previously kimiraikkonen <kimiraikkonen85(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. > 2-ID Attribute Description Threshold Value Worst Data Status > 05 Reallocated Sector Count 36 98 98 98 OK: Value is normal > That means there are 98 reallocated sectors, but still couldn't > completely understand for Seagate what "threshold - 36" means? It > shouldn't be percantage, does it mean that i'm allowed to allocate > 100-36 = 64 bad ones? (frustrating) You have bad sector number x. This inceases on more bad sectors found. By some obscure procedure that gives value y. This decreses with more bad secors found. A first hypothesist is that y decreses by 2 for every 98 bad sectors. The asumption is that the initial value was 100. Then you have threshold value z. If y ever reaches or falls below z, then you get a bad SMART status for the disk. The current speculation is that in your particular case x and y have the same numerical value, purely by accident. > 3- The other SMART values are fine as stated by many programs. Right? Looked that way. > 4- A "reallocated sector count" shows the amount of reallocated / > replaced sectors silently while the drive is operating. When the drive > has a problem with sector, first it tries to replace that sectors with > a "spare" sector thus a "reallocated sector" statistic is updated. The reallocation count will increase on any successful realocation. Reallocation can happen later. If it was unsuccesful so far, you get a "pending sector". As son as it has been reallocated, the pending secor attribut is decreased again. > If the sector is completely unreadable or unreallocatable, you see it > as "bad" marked in surface scan tools like Seatools. Did i understand > correct? Yes. > 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. 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. > Those 5 questions are the ones i see answered them clearly. > Again, thank you for following and helping. Very helpful... You are welcome. Arno |