[plug] Using a HDD with Badsectors

[Adrian Woodley]

I try to keep my drives around 30 degrees. hddtemp is your friend here.

My file server at home => http://home.diskworld.com.au/munin/Diskworld/Weatherwax.Diskworld-hddtemp_smartctl.html

Adrian

On Sun, 26 Nov 2006 08:43:50 +0800, Adrian Chadd <adrian at creative.net.au> wrote:
> On Sun, Nov 26, 2006, Timothy White wrote:
>> I have a 80Gb HDD from my sisters computer, that had developed some
>> bad sectors (2-4). It was undecided the reason for them developing was
>> the lack of cooling in the case it was at, and the high temperatures
>> it had reached.
>> I replaced her HDD, and not wanting to waste 80Gb of almost goodness,
>> I was wondering the best way to use it. After installing Ubuntu, I did
>> a "fsck.ext3 -c -c" which found 2 bad blocks. But I'm still getting a
>> few error messages in the logs.
> 
> HDD's do a few things automagically: one of the things it'll do is try
> to map bad sectors to "spare" sectors located in various spots on the
> disk.
> It'll try to re-read the data from the dodgy sector and write it to the
> new sector; and if it fails it'll return a read error and mark the sector
> invalid.
> 
> Hopefully at -that- point you can write data to that sector; it'll then
> write data for that sector to the newly-remapped spare sector (which
> isn't spare now!) and you shouldn't have any trouble.
> 
>> After seeing this, I installed smartmontools, and made sure SMART was
>> enabled on the drive, as well as setting up daily and weekly SMART
>> tests.
> 
> You should check the ongoing temperature and compare error rates to
> "corrected" rates. Also, check the relocated sector count:
> 
> On the disk below which is failing:
> 
>   5 Reallocated_Sector_Ct   0x0033   100   100   036    Pre-fail  Always  
>     -       24
> 
> On the disk next to it which isn't failing:
> 
>   5 Reallocated_Sector_Ct   0x0033   100   100   036    Pre-fail  Always  
>     -       0
> 
> You're stuck when you run out of spare sectors to reallocate into. ;)
> 
>> So far, I've gotten 3 emails from smartmon with the following messages.
>>
>> Device: /dev/sda, 1 Currently unreadable (pending) sectors
>> Device: /dev/sda, 1 Offline uncorrectable sectors
>> Device: /dev/sda, Self-Test Log error count increased from 0 to 1
> 
> Thats the disk trying to read the data from that bad sector; hopefully
> into a spare sector.
> 
>> The last message to me looks like one I can ignore, as I have
>> scheduled Self-Tests. Do I need to worry about the other 2, if I've
>> run badblocks via fsck?
> 
>> locate the blocks, and repartition so no filesystems cross the bad
>> blocks area. I'm fairly sure they are located together.
> 
> Modern HDD's, unfortuately, don't neatly map physical layout to your
> logical
> partition layout - so you might have luck or you might not have luck.
> Just run the badblocks test and see what else is picked up.
> 
> And, TBH, Netplus are doing 80gig PATA disks for $58. :) I'd suggest just
> replacing it and making sure you're setup some better cooling for next
> time.
> My current (old!) favourite tower case has a pair of fans in front of the
> HDD array and a pair of fans behind the HDD array. Very pretty!
> 
> Just for Linux HDD fun:
> 
> (lots of errors on hda, which I'm about to replace..)
> hda: dma_intr: status=0x51 { DriveReady SeekComplete Error }
> hda: dma_intr: error=0x40 { UncorrectableError }, LBAsect=156114223,
> sector=156114097
> ide: failed opcode was: unknown
> end_request: I/O error, dev hda, sector 156114097
> md: md1: sync done.
> RAID1 conf printout:
>  --- wd:2 rd:2
>  disk 0, wo:0, o:1, dev:hda2
>  disk 1, wo:0, o:1, dev:hdc2
> [root at hosting-test ~]# cat /proc/mdstat
> Personalities : [raid1]
> md0 : active raid1 hdc1[1] hda1[0]
>       521984 blocks [2/2] [UU]
> 
> md1 : active raid1 hdc2[1] hda2[0]
>       77625984 blocks [2/2] [UU]
> 
> Thanks Linux, for not degrading my software raid1 and telling me that i
> need
> to damned look at the failed disk. I hope the array doesn't fail before
> I've
> replaced hda! :) I'm glad I learnt this particular behaviour early on.
> 
> 
> Adrian
> 
> 
> 
> 
> 
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