Re: hard disk failure - now what?
On 8/24/09, Kelly Martin wrote: > I just experienced a hard drive failure on one of my FreeBSD 7.2 > production servers with no backup! I am so mad at myself for not > backing up!! Now it's a salvage operation. Here are the type of errors > I was getting on the console, over-and-over: > > ad4: TIMEOUT - WRITE_DMA48 retrying (0 retries left) LBA=441633503 > ad4: WARNING - SETFEATURES ENABLE RCACHE taskqueue timeout - > completing request directly > ad4: WARNING - SETFEATURES ENABLE WCACHE taskqueue timeout - > completing request directly > ad4: WARNING - SET_MULTI taskqueue timeout - completing request directly > ad4: FAILURE - WRITE_DMA48 timed out LBA=441633375 > g_vgs_done():ad4s1f[WRITE(offset=216338284544, length=16384)]error = 5 > > I could still login to the machine (after an eternity) but got lots of > read/write errors along the way. The offset shown in the errors kept > changing, so I thought it was a hardware eSATA controller issue > instead of a bad sector on the drive - I replaced the motherboard, > but the problem persisted. So I bought a new hard drive and have > re-installed FreeBSD 7.2 on it. I'd like to plug in the old hard drive > today, mount it and salvage as much as I can... especially the > database files, config files, etc. > > My question: what kind of checks and/or repair tools should I run on > the damaged drive after it's mounted? Or should I mount it as > read-only and start backing it up? I am hoping most of my data is > still there, but also don't want to damage it further. I desperately > need to salvage the data, what do the kind people on this list > recommend? > > thanks, > kelly If I were you, get a copy of spinrite (from grc.com) and always keep it handy. It can be risky on a drive already failing. Here's what I'd do Buy spinrite, no matter what. slave the bad drive, read-only mount.. even if the FS is dirty, read-only.. no fsck. copy the data you can (if any). reboot and run spinrite on the bad drive, deepest analysis (level 4 or 5) [may take days, weeks or even reports of months] re-slave the bad drive to the system, fsck and mount read-only. compare and copy any additional data, if any/if applicable, you can. Scrap/destroy the drive if it has sensitive data. I crack open the drive and dismantle the HDD platters from the spindle, break the read-write head ribbon cable, and remove the circuit board on the drive when I destroy drives. Each component should be recycled (being the responsible citizen), maybe on separate runs to remove the possibility of someone nosy getting into your stuff. ___ freebsd-questions@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to "freebsd-questions-unsubscr...@freebsd.org"
Re: hard disk failure - now what?
Kelly Martin writes: > I just experienced a hard drive failure on one of my FreeBSD 7.2 > production servers with no backup! I am so mad at myself for not > backing up!! Now it's a salvage operation. Here are the type of errors > I was getting on the console, over-and-over: > > ad4: TIMEOUT - WRITE_DMA48 retrying (0 retries left) LBA=441633503 > ad4: WARNING - SETFEATURES ENABLE RCACHE taskqueue timeout - > completing request directly > ad4: WARNING - SETFEATURES ENABLE WCACHE taskqueue timeout - > completing request directly > ad4: WARNING - SET_MULTI taskqueue timeout - completing request directly > ad4: FAILURE - WRITE_DMA48 timed out LBA=441633375 > g_vgs_done():ad4s1f[WRITE(offset=216338284544, length=16384)]error = 5 > > I could still login to the machine (after an eternity) but got lots of > read/write errors along the way. The offset shown in the errors kept > changing, so I thought it was a hardware eSATA controller issue > instead of a bad sector on the drive - I replaced the motherboard, > but the problem persisted. So I bought a new hard drive and have > re-installed FreeBSD 7.2 on it. I'd like to plug in the old hard drive > today, mount it and salvage as much as I can... especially the > database files, config files, etc. > > My question: what kind of checks and/or repair tools should I run on > the damaged drive after it's mounted? Or should I mount it as > read-only and start backing it up? I am hoping most of my data is > still there, but also don't want to damage it further. I desperately > need to salvage the data, what do the kind people on this list > recommend? First, try copying the entire disk, *without* mounting it. Use dd(1) to get a copy of the whole disk. I believe that "conv=noerror" may be necessary. -- Lowell Gilbert, embedded/networking software engineer, Boston area http://be-well.ilk.org/~lowell/ ___ freebsd-questions@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to "freebsd-questions-unsubscr...@freebsd.org"
Re: hard disk failure - now what?
On Mon, 24 Aug 2009 12:29:19 -0600, Kelly Martin wrote: > My question: what kind of checks and/or repair tools should I run on > the damaged drive after it's mounted? Or should I mount it as > read-only and start backing it up? Thou shalt not manipluate thy file systems while they are mounted. :-) Perform an fsck on the partitions first, then mount them ro. Copy the files you need. In case you can't "reach" essential files, you have the change to use forensic tools to get them. Finally, keep in mind that for further diagnostics and restore operations it's always wise not to use the original file systems, i. e. the original disk. Make dd copies of the partitions onto a working disk and use them instead. Luckily, most operations work on plain files as well as on block device specials. > I am hoping most of my data is > still there, but also don't want to damage it further. Good idea. This encourages you to follow the advice given above. > I desperately > need to salvage the data, what do the kind people on this list > recommend? BACKUPS!!! =^_^= -- Polytropon Magdeburg, Germany Happy FreeBSD user since 4.0 Andra moi ennepe, Mousa, ... ___ freebsd-questions@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to "freebsd-questions-unsubscr...@freebsd.org"
Re: hard disk failure - now what?
On Mon, 24 Aug 2009 14:13:22 -0600, Tim Judd wrote: > If I were you, get a copy of spinrite (from grc.com) and always keep > it handy. It can be risky on a drive already failing. Here's what > I'd do > > Buy spinrite, no matter what. Is it really such a good tool? From my own problems, I researched that common recovery tools are "R-Studio" and "UFS Explorer". Both do not natively run on BSD, but the first one offers a bootable CD. Without buying, you can run the diagnostics mode fullwise. For recovery, you need to buy the program. The "Spinrite" web page reads as follows: The industry's #1 hard drive data recovery software is NOW COMPATIBLE with NTFS, FAT, Linux, and ALL OTHER file systems! What? Linux and other file systems? Is this just marketing, in order to look good to the not very educated ones? Or do they not know what they're talking about? In fact, I will keep an eye on this program. Maybe it can help me get my data back (inode defect of $HOME entry). I'm reading their web page some more right now. > slave the bad drive, read-only mount.. even if the FS is dirty, > read-only.. no fsck. You can at least do one fsck run without any modification options, like a "read only file system check". This of course can - like any read operation on the disk - be risky if the disk is fast degrading, simply by using it. -- Polytropon Magdeburg, Germany Happy FreeBSD user since 4.0 Andra moi ennepe, Mousa, ... ___ freebsd-questions@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to "freebsd-questions-unsubscr...@freebsd.org"
Re: hard disk failure - now what?
On 8/24/09, Polytropon wrote: > On Mon, 24 Aug 2009 14:13:22 -0600, Tim Judd wrote: >> If I were you, get a copy of spinrite (from grc.com) and always keep >> it handy. It can be risky on a drive already failing. Here's what >> I'd do >> >> Buy spinrite, no matter what. > > Is it really such a good tool? From my own problems, I researched > that common recovery tools are "R-Studio" and "UFS Explorer". Both > do not natively run on BSD, but the first one offers a bootable > CD. Without buying, you can run the diagnostics mode fullwise. > For recovery, you need to buy the program. > > The "Spinrite" web page reads as follows: > > The industry's #1 hard drive data recovery > software is NOW COMPATIBLE with NTFS, > FAT, Linux, and ALL OTHER file systems! It's OS/FS independent. it works on the bits stored on the magnetic platters, NOT on a filesystem. TiVo, Linux, BSD and Mac OSX drives are treated the same. Bits on a magnetic platter. It's recovery stems from the randomization and movement of the head to the sector in question that allows it to salvage any bits it can (for example, other recovery will abandon 512bytes if 1 bit cannot be read. spinrite will recover 512bytes-1bit to a hard drive's spare sector once spinrite says "i'm done working with this sector".) It leads to a very successful rate. > > What? Linux and other file systems? > > Is this just marketing, in order to look good to the not very > educated ones? Or do they not know what they're talking about? > > In fact, I will keep an eye on this program. Maybe it can help me > get my data back (inode defect of $HOME entry). I'm reading their > web page some more right now. > Again, works on the bits. if it's a bit problem, it will do it's best to fix the problem, unless it's a hardware defect and cannot be relocated. If enough sectors are relocated, and the drive has run out of spare sectors, it's time to scrap the drive anyway. > >> slave the bad drive, read-only mount.. even if the FS is dirty, >> read-only.. no fsck. > > You can at least do one fsck run without any modification options, > like a "read only file system check". This of course can - like > any read operation on the disk - be risky if the disk is fast > degrading, simply by using it. which is why i recommend against making changes to the disk until a spinrite has completed. Personally, I setup a spinrite to be net-bootable (not officially supported). I can write a walkthrough to people who want to net-boot it. I won't provide spinrite, of course. I currently netboot: FreeBSD memtest86 spinrite with no changes to my setup any time I want to boot anything. > > -- > Polytropon > Magdeburg, Germany > Happy FreeBSD user since 4.0 > Andra moi ennepe, Mousa, ... > ___ freebsd-questions@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to "freebsd-questions-unsubscr...@freebsd.org"
Re: hard disk failure - now what?
On Mon, 24 Aug 2009 14:51:41 -0600, Tim Judd wrote: > It's OS/FS independent. it works on the bits stored on the magnetic > platters, NOT on a filesystem. Ah, I see. So it's primarily intended for diagnosing and recovering from physically defective disks. Good to know, because there are times when you exactly need to do this. So it's much more "hardware oriented" than the usual candidates for recovery programs. So the strange mentioning of "Linux and other file systems" just seems to be of a marketing nature. :-) -- Polytropon Magdeburg, Germany Happy FreeBSD user since 4.0 Andra moi ennepe, Mousa, ... ___ freebsd-questions@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to "freebsd-questions-unsubscr...@freebsd.org"
Re: hard disk failure - now what?
On 8/24/09, Polytropon wrote: > On Mon, 24 Aug 2009 14:51:41 -0600, Tim Judd wrote: >> It's OS/FS independent. it works on the bits stored on the magnetic >> platters, NOT on a filesystem. > > Ah, I see. So it's primarily intended for diagnosing and recovering > from physically defective disks. Good to know, because there are > times when you exactly need to do this. So it's much more "hardware > oriented" than the usual candidates for recovery programs. > > So the strange mentioning of "Linux and other file systems" just > seems to be of a marketing nature. :-) whatever you would like to call it, I find it accurate description of the product and it avoids false advertising. Not just diagnostics and recovery, it's for preventive maintenance, and healthy operations too. Most people who use it are in a diagnostics and recovery, but if you always use it as preventive maintenance, you'll never need to use it for diagnostics and recovery. People complain about it: "I keep running spinrite, but it never finds problems!" exactly, it's doing it's job and not having to recover. It's doing the work the drive needs to swap out bad sectors and everything. > -- > Polytropon > Magdeburg, Germany > Happy FreeBSD user since 4.0 > Andra moi ennepe, Mousa, ... > ___ freebsd-questions@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to "freebsd-questions-unsubscr...@freebsd.org"
Re: hard disk failure - now what?
On Mon, 24 Aug 2009 15:32:05 -0600, Tim Judd wrote: > Not just diagnostics and recovery, it's for preventive maintenance, > and healthy operations too. Most people who use it are in a > diagnostics and recovery, but if you always use it as preventive > maintenance, you'll never need to use it for diagnostics and recovery. > > People complain about it: "I keep running spinrite, but it never finds > problems!" exactly, it's doing it's job and not having to > recover. It's doing the work the drive needs to swap out bad sectors > and everything. Well, and its price is not as high as most recovery tools. So prevention is cheaper than intervention here. :-) -- Polytropon Magdeburg, Germany Happy FreeBSD user since 4.0 Andra moi ennepe, Mousa, ... ___ freebsd-questions@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to "freebsd-questions-unsubscr...@freebsd.org"
Re: hard disk failure - now what?
On Mon, Aug 24, 2009 at 12:29:19PM -0600, Kelly Martin wrote: > I just experienced a hard drive failure on one of my FreeBSD 7.2 > production servers with no backup! I am so mad at myself for not > backing up!! Welcome to the club. :-) > Now it's a salvage operation. Here are the type of errors > I was getting on the console, over-and-over: > > ad4: TIMEOUT - WRITE_DMA48 retrying (0 retries left) LBA=441633503 > ad4: WARNING - SETFEATURES ENABLE RCACHE taskqueue timeout - > completing request directly > ad4: WARNING - SETFEATURES ENABLE WCACHE taskqueue timeout - > completing request directly > ad4: WARNING - SET_MULTI taskqueue timeout - completing request directly > ad4: FAILURE - WRITE_DMA48 timed out LBA=441633375 > g_vgs_done():ad4s1f[WRITE(offset=216338284544, length=16384)]error = 5 It _could_ just be a bad or improperly connected SATA cable. Try changing or re-seating the cable. Read errors cannot damage your data, but write errors can! Immediately stop all writing to the disk. Re-mount the partitions on that disk as read-only, or unmount them. To see if a disk really is broken, install sysutils/smartmontools, and run 'smartctl -a' on the disk. If you see errors in its report (e.g. reallocated sectors), the disk is dying and should be unplugged to prevent it from getting worse. > My question: what kind of checks and/or repair tools should I run on > the damaged drive after it's mounted? As others have mentioned, first make a copy (with the disk unmounted) of the partitions on that disk with dd, saving them to another drive. That way you can experiment with the data without further deterioration of the original. You can use this disk image e.g. as a vnode-backed memory disk, see mdconfig(8). If you cannot get a good copy of the disk partitions it might be a good idea to get a quote from a professional hard drive data recovery company to do that for you. I've never had occasion to try this (hooray for backups) but I've heard it can be quite expensive. :-/ Try using fsck_ffs on (copies of) the disk image to see if that can restore the damage. If the damage is beyond repair for fsck_ffs, you have a real problem. Of course is you have a good disk image, your data is still there, but you might have to use a forensics program like sysutils/sleuthkit or hexdump to try and piece files together. And even then you cannot be sure that there is no corrupted data in the files themselves. Good luck with that. :-( Roland -- R.F.Smith http://www.xs4all.nl/~rsmith/ [plain text _non-HTML_ PGP/GnuPG encrypted/signed email much appreciated] pgp: 1A2B 477F 9970 BA3C 2914 B7CE 1277 EFB0 C321 A725 (KeyID: C321A725) pgpG8KHu4CLdA.pgp Description: PGP signature
Re: hard disk failure - now what?
Lowell Gilbert wrote: > Kelly Martin writes: > > I just experienced a hard drive failure on one of my > > FreeBSD 7.2 production servers with no backup! ... > First, try copying the entire disk, *without* mounting it. Yep. > Use dd(1) to get a copy of the whole disk. I believe that > "conv=noerror" may be necessary. Much better: use sysutils/ddrescue, which was written specifically to deal with this sort of situation. ___ freebsd-questions@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to "freebsd-questions-unsubscr...@freebsd.org"
Re: hard disk failure - now what?
On Mon, Aug 24, 2009 at 10:26:11PM +0200, Polytropon wrote: > On Mon, 24 Aug 2009 12:29:19 -0600, Kelly Martin > wrote: > > My question: what kind of checks and/or repair tools should I run on > > the damaged drive after it's mounted? Or should I mount it as > > read-only and start backing it up? > > Thou shalt not manipluate thy file systems while they are mounted. :-) > Perform an fsck on the partitions first, then mount them ro. Copy > the files you need. > > In case you can't "reach" essential files, you have the change to > use forensic tools to get them. > > Finally, keep in mind that for further diagnostics and restore > operations it's always wise not to use the original file systems, > i. e. the original disk. Make dd copies of the partitions onto > a working disk and use them instead. Luckily, most operations > work on plain files as well as on block device specials. dd will barf on bad bits too. You can tinker to make it skip over the bad block, but it won't read it. jerry > > > I am hoping most of my data is > > still there, but also don't want to damage it further. > > Good idea. This encourages you to follow the advice given above. > > > > > I desperately > > need to salvage the data, what do the kind people on this list > > recommend? > > BACKUPS!!! =^_^= > > > > -- > Polytropon > Magdeburg, Germany > Happy FreeBSD user since 4.0 > Andra moi ennepe, Mousa, ... > ___ > freebsd-questions@freebsd.org mailing list > http://lists.freebsd.org/mailman/listinfo/freebsd-questions > To unsubscribe, send any mail to "freebsd-questions-unsubscr...@freebsd.org" ___ freebsd-questions@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to "freebsd-questions-unsubscr...@freebsd.org"
Re: hard disk failure - now what?
per...@pluto.rain.com writes: > Lowell Gilbert wrote: >> Kelly Martin writes: >> > I just experienced a hard drive failure on one of my >> > FreeBSD 7.2 production servers with no backup! > ... >> First, try copying the entire disk, *without* mounting it. > > Yep. > >> Use dd(1) to get a copy of the whole disk. I believe that >> "conv=noerror" may be necessary. > > Much better: use sysutils/ddrescue, which was written > specifically to deal with this sort of situation. Excellent suggestion. -- Lowell Gilbert, embedded/networking software engineer, Boston area http://be-well.ilk.org/~lowell/ ___ freebsd-questions@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to "freebsd-questions-unsubscr...@freebsd.org"
Re: hard disk failure - now what?
On Tue, 25 Aug 2009 11:04:38 -0400, Jerry McAllister wrote: > dd will barf on bad bits too. > You can tinker to make it skip over the bad block, but it > won't read it. As it has been suggested, there are interesting tools in the ports collection. I'll post my "famous list" again. Among them, note ddrescue and dd_rescue. But base system tools such as the fetch program can help. System: dd fsck_ffs clri fsdb fetch -rR recoverdisk (!) Ports: ddrescue dd_rescue ffs2recov magicrescue testdisk The Sleuth Kit: fls dls ils autopsy scan_ffs recoverjpeg foremost photorec Those programs are not ordered in any way. -- Polytropon Magdeburg, Germany Happy FreeBSD user since 4.0 Andra moi ennepe, Mousa, ... ___ freebsd-questions@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to "freebsd-questions-unsubscr...@freebsd.org"
Re: hard disk failure - now what?
First, thanks to everyone for the really great replies. Many suggestions were quite helpful and have kept me on track. I'll quote a couple of people and then add some comments below. On Mon, Aug 24, 2009 at 4:32 PM, Roland Smith wrote: > It _could_ just be a bad or improperly connected SATA cable. Try changing or > re-seating the cable. I thought of that too, but no luck. > Read errors cannot damage your data, but write errors can! Immediately stop > all writing to the disk. Re-mount the partitions on that disk as read-only, or > unmount them. That was a consensus among everyone who replied, so I made that step #1. I mounted the partitions read-only and crossed my fingers. Trying to check the integrity of the data, or even get directory listings was another matter, as I got various strange errors... which told me I quite likely had some data loss. > To see if a disk really is broken, install sysutils/smartmontools, and run > 'smartctl -a' on the disk. If you see errors in its report (e.g. reallocated > sectors), the disk is dying and should be unplugged to prevent it from getting > worse. That's a good idea and I'll try to use it in the future. After plugging the drive in and accessing it, I heard those tell-tale signs of hard drive failure: clicks and pops and other unusual noises, so I know that it has some damage. I hate those sounds, having heard them on failing drives too many times before. > >> My question: what kind of checks and/or repair tools should I run on >> the damaged drive after it's mounted? > > As others have mentioned, first make a copy (with the disk unmounted) of the > partitions on that disk with dd, saving them to another drive. That way you > can experiment with the data without further deterioration of the > original. I ran dd and it took over 20 hours to complete. In fact it just finished this evening, after running all day. Lots of FAILURE errors were reported along the way, enough to fill two console screens or more. And of course to complicate things I didn't have a spare drive as an output device that was the *same size*, so I used a smaller drive thinking that it wouldn't matter since the source drive wasn't full anyway. I have no idea if data is scattered around on the FFS filesystem such that cloning a mostly empty, larger drive onto something smaller might lose data... I searched Google and couldn't find the answer, so I proceeded anyway. It doesn't matter now though, as I have a new drive now and another plan. >You can use this disk image e.g. as a vnode-backed memory disk, see > mdconfig(8). If you cannot get a good copy of the disk partitions it might be > a good idea to get a quote from a professional hard drive data recovery > company to do that for you. I've never had occasion to try this (hooray for > backups) but I've heard it can be quite expensive. :-/ I'm going to try dd a second time, but this time I'll use ddrescue as some people suggested and I'll make the target drive an identical-sized 500 Gbyte drive, which I purchased today. I imagine it will take a long time to create this cloned disk... hopefully with fewer errors than dd gave me, though we'll see. > Try using fsck_ffs on (copies of) the disk image to see if that can restore > the damage. If the damage is beyond repair for fsck_ffs, you have a real > problem. Of course is you have a good disk image, your data is still > there, but you might have to use a forensics program like sysutils/sleuthkit > or hexdump to try and piece files together. And even then you cannot be sure > that there is no corrupted data in the files themselves. Good luck with that. > :-( Indeed some of the partitions seem to be beyond repair. In particular my /var partition is totally fubar'ed. When using fsck_ffs I got all sorts of errors when trying to repair the partition, things like: BAD SUPER BLOCK: VALUES IN SUPER BLOCK DISAGREE WITH THOSE IN FIRST ALTERNATE So I used the -b option suggested in the man page, "fsck_ffs -y -b 160 /dev/ad0s1d" and it ran and fixed a few things, but then stopped with the following error: fsck_ufs: cannot alloc 4294967292 bytes for inoinfo The worst part of all is that the /var partition would normally be okay to lose if it didn't have my MySQL database on it - the most important data on the server. I just about choked down a golf ball when I discovered my /var partition was in such rough shape and I might be forced to use real recovery tools, or hire a professional for $$$, or be out-of-luck. MySQL databases are normally stored in /var/db/mysql. But then I remembered my MySQL server was actually running in a Jail environment, and therefore it was located at /usr/jails/myjail/var/db/mysql instead of /var/db/mysql, and therefore the jailed MySQL database was on a totally different partition. Lucky! And I was also very lucky that I could mount the large /usr partition in read-only mode and copy off the most critical files I needed, starting with the database. No errors on that part o
Re: hard disk failure - now what?
On Mon, Aug 24, 2009 at 02:51:41PM -0600, Tim Judd wrote: > >> Buy spinrite, no matter what. > > It's OS/FS independent. it works on the bits stored on the magnetic > platters, NOT on a filesystem. TiVo, Linux, BSD and Mac OSX drives > are treated the same. Bits on a magnetic platter. It's recovery > stems from the randomization and movement of the head to the sector in > question that allows it to salvage any bits it can (for example, other > recovery will abandon 512bytes if 1 bit cannot be read. spinrite will > recover 512bytes-1bit to a hard drive's spare sector once spinrite > says "i'm done working with this sector".) It leads to a very > successful rate. (Disclaimer: I'm not familiar with spinrite.) 512bytes-1bit may be read back, but you can't be sure that those are the correct bytes! IIRC, sectors are usually protected by some kind of ECC. Simply ignoring the ECC and reading raw magnetic data will all too often result in corrupt sectors. Of course, if you have out-of-band error correction or at least error detection mechanisms (like .PAR or md5/sha1 checksums), raw magnetic recovery is better than nothing, if you're desperate. -cpghost. -- Cordula's Web. http://www.cordula.ws/ ___ freebsd-questions@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to "freebsd-questions-unsubscr...@freebsd.org"
Re: hard disk failure - now what?
On Wed, 26 Aug 2009 18:10:38 +0200 cpghost wrote: > On Mon, Aug 24, 2009 at 02:51:41PM -0600, Tim Judd wrote: > > >> Buy spinrite, no matter what. > > > > It's OS/FS independent. it works on the bits stored on the magnetic > > platters, NOT on a filesystem. TiVo, Linux, BSD and Mac OSX drives > > are treated the same. Bits on a magnetic platter. It's recovery > > stems from the randomization and movement of the head to the sector > > in question that allows it to salvage any bits it can (for example, > > other recovery will abandon 512bytes if 1 bit cannot be read. > > spinrite will recover 512bytes-1bit to a hard drive's spare sector > > once spinrite says "i'm done working with this sector".) It leads > > to a very successful rate. > > (Disclaimer: I'm not familiar with spinrite.) > > 512bytes-1bit may be read back, but you can't be sure that those are > the correct bytes! IIRC, sectors are usually protected by some kind of > ECC. Simply ignoring the ECC and reading raw magnetic data will all > too often result in corrupt sectors. > > Of course, if you have out-of-band error correction or at least error > detection mechanisms (like .PAR or md5/sha1 checksums), raw magnetic > recovery is better than nothing, if you're desperate. > > -cpghost. I have used Spinrite several times with excellent results. In fact, I recently used it to recover a Laptop drive that had become unusable. Spinrite tries to turn off ECC if possible. It is not the cheapest product; however, it works better than anything else I have tried on bonked discs. Use it on its highest recover level and it will recover the drive; although it may take a while. http://www.grc.com/intro.htm -- Jerry ges...@yahoo.com Lord, defend me from my friends; I can account for my enemies. Charles D'Hericault ___ freebsd-questions@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to "freebsd-questions-unsubscr...@freebsd.org"
Re: hard disk failure - now what?
On Tue, Aug 25, 2009 at 11:46:50PM -0600, Kelly Martin wrote: > plugging the drive in and accessing it, I heard those tell-tale signs > of hard drive failure: clicks and pops and other unusual noises, so I > know that it has some damage. I hate those sounds, having heard them > on failing drives too many times before. If the drive is that bad, it is doubtfull if dd or ddrescue will be able to get a good copy. > >> My question: what kind of checks and/or repair tools should I run on > >> the damaged drive after it's mounted? > > > > As others have mentioned, first make a copy (with the disk unmounted) of the > > partitions on that disk with dd, saving them to another drive. That way you > > can experiment with the data without further deterioration of the > > original. > > I ran dd and it took over 20 hours to complete. In fact it just > finished this evening, after running all day. Lots of FAILURE errors > were reported along the way, enough to fill two console screens or > more. And of course to complicate things I didn't have a spare drive > as an output device that was the *same size*, so I used a smaller > drive thinking that it wouldn't matter since the source drive wasn't > full anyway. I have no idea if data is scattered around on the FFS > filesystem such that cloning a mostly empty, larger drive onto > something smaller might lose data... I searched Google and couldn't > find the answer, so I proceeded anyway. It doesn't matter now though, > as I have a new drive now and another plan. Using dd you make a block-for block copy; dd doesn't know about filesystems. You could pipe the output from dd through a compression program like gzip or bzip2. That could yield a smaller image. But you'd have to uncompress it in order to use it. Or you could try just copying the filesystems separately. E.g. copy from ad4s1f instead of the whole ad4. That way you can split the data over several files which you can store in different places. > I'm going to try dd a second time, but this time I'll use ddrescue as > some people suggested and I'll make the target drive an > identical-sized 500 Gbyte drive, which I purchased today. I imagine it > will take a long time to create this cloned disk... hopefully with > fewer errors than dd gave me, though we'll see. I hope you get a good copy, but it doesn't sound too likely. I'm not a hardware expert, but if the disk is really breaking down in the hardware or electronics, it is not inconceivable that even reading might further deteriorate it. If you do not get a good 1:1 copy, you'll have extra errors in your data! Depending on the options you give dd, it will either skip blocks with errors or fill it with zeroes or other characters. See the piece of the manual page of fsck_ufs that describes the 'noerror' conversion. > Indeed some of the partitions seem to be beyond repair. In particular > my /var partition is totally fubar'ed. When using fsck_ffs I got all > sorts of errors when trying to repair the partition, things like: > > BAD SUPER BLOCK: VALUES IN SUPER BLOCK DISAGREE WITH THOSE IN FIRST ALTERNATE > So I used the -b option suggested in the man page, "fsck_ffs -y -b 160 > /dev/ad0s1d" and it ran and fixed a few things, but then stopped with > the following error: > > fsck_ufs: cannot alloc 4294967292 bytes for inoinfo The meaning of errors is explained in Appendix A of "Fsck - The UNIX File System Check Program". You can find it this as /usr/share/doc/smm/03.fsck/paper.ascii.gz > MySQL databases are normally stored in /var/db/mysql. But then I > remembered my MySQL server was actually running in a Jail environment, > and therefore it was located at /usr/jails/myjail/var/db/mysql instead > of /var/db/mysql, and therefore the jailed MySQL database was on a > totally different partition. Lucky! And I was also very lucky that I > could mount the large /usr partition in read-only mode and copy off > the most critical files I needed, starting with the database. No > errors on that part of the disk so far, at least with the few critical > files I've copied over. Whew! Congratulations! > Until just a few minutes ago I didn't think there'd be a happy ending. > But I've got the most critical data copied over now, the rest can > wait. I'm going to go run dd a second time (well, ddrescue) now and > then start work on the copy once it finishes, in a day or two. Time to start thinking about a solid backup strategy as well. :-) Roland -- R.F.Smith http://www.xs4all.nl/~rsmith/ [plain text _non-HTML_ PGP/GnuPG encrypted/signed email much appreciated] pgp: 1A2B 477F 9970 BA3C 2914 B7CE 1277 EFB0 C321 A725 (KeyID: C321A725) pgpOcLejmqquP.pgp Description: PGP signature
Re: hard disk failure - now what?
On Wed, Aug 26, 2009 at 08:07:41PM +0200, Roland Smith wrote: > On Tue, Aug 25, 2009 at 11:46:50PM -0600, Kelly Martin wrote: > > plugging the drive in and accessing it, I heard those tell-tale > > signs of hard drive failure: clicks and pops and other unusual > > noises, so I know that it has some damage. I hate those sounds, > > having heard them on failing drives too many times before. > > If the drive is that bad, it is doubtfull if dd or ddrescue will be > able to get a good copy. Probably true. I hesitate to suggest this, but sticking the drive in a freezer (preferrably in a ziplock bag) for a few hours or overnight might help. Stories from people claiming "I swear it works!" go back years. To the exent it does work, it might give Kelly enough time to attempt recovery. If more time is required, he can try and find a creative workaround for the 5 meter max length for USB cables. Also, experimenting with dry ice or acetone baths might prove to be interesting, or at least educational. ;-) -- George ___ freebsd-questions@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to "freebsd-questions-unsubscr...@freebsd.org"
Re: hard disk failure - now what?
On Wed, Aug 26, 2009 at 12:13:48PM -0700, George Davidovich wrote: > > If the drive is that bad, it is doubtfull if dd or ddrescue will be > > able to get a good copy. > > Probably true. I hesitate to suggest this, but sticking the drive in a > freezer (preferrably in a ziplock bag) for a few hours or overnight > might help. Stories from people claiming "I swear it works!" go back > years. Interesting. > To the exent it does work, it might give Kelly enough time to attempt > recovery. If more time is required, he can try and find a creative > workaround for the 5 meter max length for USB cables. Also, > experimenting with dry ice or acetone baths might prove to be > interesting, or at least educational. ;-) Acetone and electronics are _not_ a good mix! Acetone is extremely flammable. It evaporates easily and can form explosive mixtures in air over a wide range of concentrations. Not to mention that it would degrade/destroy printed circuit boards; acetone breaks down the resin that binds the glass fibers in the laminates! Not as fast as n-Methyl-2-pyrrolidone, bus fast enough. I remember this special non-condictive 3M fluid that can be used to cool electronics. A group of hackers dunked a complete PC minus the case and power supply in this stuff. The fluid itself was cooled with liquid nitrogen. They everclocked it something wicked. Not very practical though. :-) Roland -- R.F.Smith http://www.xs4all.nl/~rsmith/ [plain text _non-HTML_ PGP/GnuPG encrypted/signed email much appreciated] pgp: 1A2B 477F 9970 BA3C 2914 B7CE 1277 EFB0 C321 A725 (KeyID: C321A725) pgpXZwydo45KR.pgp Description: PGP signature
Re: hard disk failure - now what?
On Wed, Aug 26, 2009 at 10:23:47PM +0200, Roland Smith wrote: > On Wed, Aug 26, 2009 at 12:13:48PM -0700, George Davidovich wrote: > > > > If the drive is that bad, it is doubtfull if dd or ddrescue will be > > > able to get a good copy. > > > > Probably true. I hesitate to suggest this, but sticking the drive in a > > freezer (preferrably in a ziplock bag) for a few hours or overnight > > might help. Stories from people claiming "I swear it works!" go back > > years. > > Interesting. > > > To the exent it does work, it might give Kelly enough time to attempt > > recovery. If more time is required, he can try and find a creative > > workaround for the 5 meter max length for USB cables. Also, > > experimenting with dry ice or acetone baths might prove to be > > interesting, or at least educational. ;-) > > > I remember this special non-condictive 3M fluid that can be used to cool > electronics. A group of hackers dunked a complete PC minus the case and power > supply in this stuff. The fluid itself was cooled with liquid nitrogen. They > everclocked it something wicked. Not very practical though. :-) A number of supercomputers from Cray and Control Data and maybe some other places used this sort of thing on some experimental systems. I don't know if any ever were put in to commercial production. They submerged who boards in to it and then supercooled the fluid. I don't remember the chemical names. The fluid was a relative of Freon and held sufficient levels of oxygen to support lung breathers. They used to have a tank with a live mouse submerged in it bouncing around and seeming to have no trouble not choking or drowning. A variation of it was also researched as a blood substitute for some special medical needs. I don't know how far that went.I know it is not all fantasy because I saw the live mouse. I didn't try the blood substitute. jerry > > Roland > -- > R.F.Smith http://www.xs4all.nl/~rsmith/ > [plain text _non-HTML_ PGP/GnuPG encrypted/signed email much appreciated] > pgp: 1A2B 477F 9970 BA3C 2914 B7CE 1277 EFB0 C321 A725 (KeyID: C321A725) ___ freebsd-questions@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to "freebsd-questions-unsubscr...@freebsd.org"
Re: hard disk failure - now what?
On Wed, 26 Aug 2009 12:13:48 -0700, George Davidovich wrote: > Probably true. I hesitate to suggest this, but sticking the drive in a > freezer (preferrably in a ziplock bag) for a few hours or overnight > might help. Stories from people claiming "I swear it works!" go back > years. I heared a similar suggestion from a guy who tried to get the protection code out of a car radio. :-) > To the exent it does work, it might give Kelly enough time to attempt > recovery. If more time is required, he can try and find a creative > workaround for the 5 meter max length for USB cables. 5 meters? I always thought USB is specified for 2 meters only. I've never seen a 5 meters long USB cable, by the way. -- Polytropon Magdeburg, Germany Happy FreeBSD user since 4.0 Andra moi ennepe, Mousa, ... ___ freebsd-questions@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to "freebsd-questions-unsubscr...@freebsd.org"
Re: hard disk failure - now what?
On Wed, Aug 26, 2009 at 04:45:40PM -0400, Jerry McAllister wrote: > On Wed, Aug 26, 2009 at 10:23:47PM +0200, Roland Smith wrote: > > > On Wed, Aug 26, 2009 at 12:13:48PM -0700, George Davidovich wrote: I > > remember this special non-condictive 3M fluid that can be used to > > cool electronics. A group of hackers dunked a complete PC minus the > > case and power supply in this stuff. The fluid itself was cooled > > with liquid nitrogen. They everclocked it something wicked. Not very > > practical though. :-) > > A number of supercomputers from Cray and Control Data and maybe some > other places used this sort of thing on some experimental systems. I > don't know if any ever were put in to commercial production. They > submerged who boards in to it and then supercooled the fluid. I > don't remember the chemical names. I do, but have no idea why. http://en.wikipedia.org/wiki/Perfluorohexane > The fluid was a relative of Freon and held sufficient levels of oxygen > to support lung breathers. They used to have a tank with a live mouse > submerged in it bouncing around and seeming to have no trouble not > choking or drowning. > A variation of it was also researched as a blood substitute for some > special medical needs. I don't know how far that went.I know it > is not all fantasy because I saw the live mouse. I believe you. I saw a similar scene in a movie, so I already knew it had to be true. Bonus points for anyone that can add to this thread's collection of off-topic but semi-interesting trivia and name the movie. > I didn't try the blood substitute. How do you save a drowning mouse? Use mouse to mouse resuscitation. Thanks, I'll be here all week. Try the veal instead. -- George ___ freebsd-questions@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to "freebsd-questions-unsubscr...@freebsd.org"
Re: hard disk failure - now what?
On Aug 26, 2009, at 14:14:51, George Davidovich wrote: I believe you. I saw a similar scene in a movie, so I already knew it had to be true. Bonus points for anyone that can add to this thread's collection of off-topic but semi-interesting trivia and name the movie. What is "The Abyss" for 1000, Alex? :) Scott ___ freebsd-questions@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to "freebsd-questions-unsubscr...@freebsd.org"
RE: hard disk failure - now what?
I had a laptop years ago that started to die, but seemed to work OK when first removed from a cold car. After an hour or so it would die. I eventually put it in the freezer long enough to get what I needed off the drive, so in some cases I would agree that cold is good! -Original Message- From: owner-freebsd-questi...@freebsd.org [mailto:owner-freebsd-questi...@freebsd.org] On Behalf Of Polytropon Sent: Wednesday, August 26, 2009 4:13 PM To: George Davidovich Cc: freebsd-questions@freebsd.org Subject: Re: hard disk failure - now what? On Wed, 26 Aug 2009 12:13:48 -0700, George Davidovich wrote: > Probably true. I hesitate to suggest this, but sticking the drive in a > freezer (preferrably in a ziplock bag) for a few hours or overnight > might help. Stories from people claiming "I swear it works!" go back > years. I heared a similar suggestion from a guy who tried to get the protection code out of a car radio. :-) > To the exent it does work, it might give Kelly enough time to attempt > recovery. If more time is required, he can try and find a creative > workaround for the 5 meter max length for USB cables. 5 meters? I always thought USB is specified for 2 meters only. I've never seen a 5 meters long USB cable, by the way. -- Polytropon Magdeburg, Germany Happy FreeBSD user since 4.0 Andra moi ennepe, Mousa, ... ___ freebsd-questions@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to "freebsd-questions-unsubscr...@freebsd.org" "This email is intended to be reviewed by only the intended recipient and may contain information that is privileged and/or confidential. If you are not the intended recipient, you are hereby notified that any review, use, dissemination, disclosure or copying of this email and its attachments, if any, is strictly prohibited. If you have received this email in error, please immediately notify the sender by return email and delete this email from your system." ___ freebsd-questions@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to "freebsd-questions-unsubscr...@freebsd.org"
Re: hard disk failure - now what?
On Wed, Aug 26, 2009 at 02:14:51PM -0700, George Davidovich wrote: > > > > A number of supercomputers from Cray and Control Data and maybe some > > other places used this sort of thing on some experimental systems. I > > don't know if any ever were put in to commercial production. They > > submerged who boards in to it and then supercooled the fluid. I > > don't remember the chemical names. > > I do, but have no idea why. > > http://en.wikipedia.org/wiki/Perfluorohexane > > > The fluid was a relative of Freon and held sufficient levels of oxygen > > to support lung breathers. They used to have a tank with a live mouse > > submerged in it bouncing around and seeming to have no trouble not > > choking or drowning. > > > A variation of it was also researched as a blood substitute for some > > special medical needs. I don't know how far that went.I know it > > is not all fantasy because I saw the live mouse. > > I believe you. I saw a similar scene in a movie, so I already knew it > had to be true. Bonus points for anyone that can add to this thread's > collection of off-topic but semi-interesting trivia and name the movie. I vaguely remember a movie with it in, but I saw it in person at Cray headquarters back when. > > > I didn't try the blood substitute. > > How do you save a drowning mouse? > Use mouse to mouse resuscitation. > > Thanks, I'll be here all week. Try the veal instead. Only with the asparagus. jerry > > -- > George > ___ > freebsd-questions@freebsd.org mailing list > http://lists.freebsd.org/mailman/listinfo/freebsd-questions > To unsubscribe, send any mail to "freebsd-questions-unsubscr...@freebsd.org" ___ freebsd-questions@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to "freebsd-questions-unsubscr...@freebsd.org"
Re: hard disk failure - now what?
On Wed, 26 Aug 2009 16:30:59 -0500, "Gary Gatten" wrote: > I had a laptop years ago that started to die, but seemed to work OK when > first removed from a cold car. After an hour or so it would die. I > eventually put it in the freezer long enough to get what I needed off > the drive, so in some cases I would agree that cold is good! That really sounds like a thermal problem (defective cooling)... -- Polytropon Magdeburg, Germany Happy FreeBSD user since 4.0 Andra moi ennepe, Mousa, ... ___ freebsd-questions@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to "freebsd-questions-unsubscr...@freebsd.org"
RE: hard disk failure - now what?
Naw, I don't recall the POST error exactly, but from what I remember it couldn't find a boot device. Could've been the controller, but from what I recall I swapped the drive (later) and all was good. I really don't recall though - I could've put the "bad" drive in a good laptop and fixed it that way - really don't recall details. Wish I could fix some other problems by throwing them in a freezer! -Original Message- From: Polytropon [mailto:free...@edvax.de] Sent: Wednesday, August 26, 2009 5:54 PM To: Gary Gatten Cc: George Davidovich; freebsd-questions@freebsd.org Subject: Re: hard disk failure - now what? On Wed, 26 Aug 2009 16:30:59 -0500, "Gary Gatten" wrote: > I had a laptop years ago that started to die, but seemed to work OK when > first removed from a cold car. After an hour or so it would die. I > eventually put it in the freezer long enough to get what I needed off > the drive, so in some cases I would agree that cold is good! That really sounds like a thermal problem (defective cooling)... -- Polytropon Magdeburg, Germany Happy FreeBSD user since 4.0 Andra moi ennepe, Mousa, ... "This email is intended to be reviewed by only the intended recipient and may contain information that is privileged and/or confidential. If you are not the intended recipient, you are hereby notified that any review, use, dissemination, disclosure or copying of this email and its attachments, if any, is strictly prohibited. If you have received this email in error, please immediately notify the sender by return email and delete this email from your system." ___ freebsd-questions@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to "freebsd-questions-unsubscr...@freebsd.org"
Re: hard disk failure - now what?
On Wed, 26 Aug 2009 20:07:41 +0200, Roland Smith wrote:
> If the drive is that bad, it is doubtfull if dd or ddrescue will be able to
> get a good copy.
There's an additional problem: Let's assume dd creates an 1:1 copy
of the file system in its actual state - nobody guarantees that
this file system is fully intact, or can be repaired.
I have (!) the problem myself that I got the dd copy from the partition
holding my home directory just fine, but the file system itself is
damaged in such a state that fsck_ffs cannot repair it. At least, I
could get data off it - EXCEPT my home directory, sadly. But that's
not a (physical) disk problem, but a file system related one.
> Using dd you make a block-for block copy; dd doesn't know about filesystems.
> You could pipe the output from dd through a compression program like gzip or
> bzip2. That could yield a smaller image. But you'd have to uncompress it in
> order to use it.
I'm often told that hard disks are cheap today, and it's much
more relaxing operating on a plain image than on a compressed
one.
> Or you could try just copying the filesystems separately. E.g. copy from
> ad4s1f instead of the whole ad4. That way you can split the data over several
> files which you can store in different places.
That is the encouraged method. In case you have separated file
systems, it's a quite optimum case. For example, you don't need
to mess around with a 20 GB /tmp partition if you intendedly want
to lose its "data".
> I hope you get a good copy, but it doesn't sound too likely. I'm not a
> hardware
> expert, but if the disk is really breaking down in the hardware or
> electronics, it is not inconceivable that even reading might further
> deteriorate it.
In case of such hardware defects that causes growing problems,
it's wise to get the data (1st) as fast as possible and (2nd)
as accurate as possible - before the disk completely dies.
In such a case, it's still possible to recover data, e. g. to
mount the disks (the cylinders or platters) into another drive
unit. But if the disks are defective theirselves...
> If you do not get a good 1:1 copy, you'll have extra errors in
> your data! Depending on the options you give dd, it will either skip blocks
> with errors or fill it with zeroes or other characters. See the piece of the
> manual page of fsck_ufs that describes the 'noerror' conversion.
As far as I remember, dd_rescue or ddrescue can handle such
problems. In case of errors, they retry and keep reading.
> > fsck_ufs: cannot alloc 4294967292 bytes for inoinfo
>
> The meaning of errors is explained in Appendix A of "Fsck - The UNIX File
> System Check Program". You can find it this as
> /usr/share/doc/smm/03.fsck/paper.ascii.gz
When I tried to repair my defective partition in another system
with less RAM, I got a similar error:
cannot alloc 1073796864 bytes for inoinfo
The real ("usual") error is
fsck_4.2bsd: bad inode number 306176 to nextinode
It seems that more RAM is needed to store information.
> Time to start thinking about a solid backup strategy as well. :-)
The correct time to do so is BEFORE you start storing data. :-)
--
Polytropon
Magdeburg, Germany
Happy FreeBSD user since 4.0
Andra moi ennepe, Mousa, ...
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Re: hard disk failure - now what?
Gary Gatten wrote: I had a laptop years ago that started to die, but seemed to work OK when first removed from a cold car. After an hour or so it would die. I eventually put it in the freezer long enough to get what I needed off the drive, so in some cases I would agree that cold is good! -Original Message- From: owner-freebsd-questi...@freebsd.org [mailto:owner-freebsd-questi...@freebsd.org] On Behalf Of Polytropon Sent: Wednesday, August 26, 2009 4:13 PM To: George Davidovich Cc: freebsd-questions@freebsd.org Subject: Re: hard disk failure - now what? On Wed, 26 Aug 2009 12:13:48 -0700, George Davidovich wrote: Probably true. I hesitate to suggest this, but sticking the drive in a freezer (preferrably in a ziplock bag) for a few hours or overnight might help. Stories from people claiming "I swear it works!" go back years. I heared a similar suggestion from a guy who tried to get the protection code out of a car radio. :-) To the exent it does work, it might give Kelly enough time to attempt recovery. If more time is required, he can try and find a creative workaround for the 5 meter max length for USB cables. 5 meters? I always thought USB is specified for 2 meters only. I've never seen a 5 meters long USB cable, by the way. Aloha, Off Topic but very funny as well as interesting. I have a usb cable that I bought it on line and have used it for a small video camera that is 15 meters long and it works OK. ~Al Plant - Honolulu, Hawaii - Phone: 808-284-2740 + http://hawaiidakine.com + http://freebsdinfo.org + + http://aloha50.net - Supporting - FreeBSD 6.* - 7.* - 8.* + < email: n...@hdk5.net > "All that's really worth doing is what we do for others."- Lewis Carrol ___ freebsd-questions@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to "freebsd-questions-unsubscr...@freebsd.org"
Re: hard disk failure - now what?
On Thu, Aug 27, 2009 at 01:03:58AM +0200, Polytropon wrote: > On Wed, 26 Aug 2009 20:07:41 +0200, Roland Smith wrote: > > If the drive is that bad, it is doubtfull if dd or ddrescue will be able to > > get a good copy. > > There's an additional problem: Let's assume dd creates an 1:1 copy > of the file system in its actual state - nobody guarantees that > this file system is fully intact, or can be repaired. Certainly. If filesystem data is missing, there is only so much that fsck_ufs can do about it. > > Using dd you make a block-for block copy; dd doesn't know about filesystems. > > You could pipe the output from dd through a compression program like gzip or > > bzip2. That could yield a smaller image. But you'd have to uncompress it in > > order to use it. > > I'm often told that hard disks are cheap today, and it's much > more relaxing operating on a plain image than on a compressed > one. Of course. But if you are operating under restricted scape constraints... > > I hope you get a good copy, but it doesn't sound too likely. I'm not a > > hardware expert, but if the disk is really breaking down in the hardware > > or electronics, it is not inconceivable that even reading might further > > deteriorate it. > > In case of such hardware defects that causes growing problems, > it's wise to get the data (1st) as fast as possible and (2nd) > as accurate as possible - before the disk completely dies. And (3rd) in as few tries as possible! > In such a case, it's still possible to recover data, e. g. to > mount the disks (the cylinders or platters) into another drive > unit. But if the disks are defective theirselves... I wonder if that is still possible with current drives? My impression was (from a paper that I can't locate ATM) that data densities are so high that it is extremely difficult to read the data with different arm/head assembly then the one it was written with. > > Time to start thinking about a solid backup strategy as well. :-) > > The correct time to do so is BEFORE you start storing data. :-) Very true! But since the lack of backups was what got the OP in this mess in the first place... Roland -- R.F.Smith http://www.xs4all.nl/~rsmith/ [plain text _non-HTML_ PGP/GnuPG encrypted/signed email much appreciated] pgp: 1A2B 477F 9970 BA3C 2914 B7CE 1277 EFB0 C321 A725 (KeyID: C321A725) pgpuFA9QD2zWP.pgp Description: PGP signature
Re: hard disk failure - now what?
George Davidovich wrote: On Wed, Aug 26, 2009 at 04:45:40PM -0400, Jerry McAllister wrote: On Wed, Aug 26, 2009 at 10:23:47PM +0200, Roland Smith wrote: On Wed, Aug 26, 2009 at 12:13:48PM -0700, George Davidovich wrote: I remember this special non-condictive 3M fluid that can be used to cool electronics. A group of hackers dunked a complete PC minus the case and power supply in this stuff. The fluid itself was cooled with liquid nitrogen. They everclocked it something wicked. Not very practical though. :-) A number of supercomputers from Cray and Control Data and maybe some other places used this sort of thing on some experimental systems. I don't know if any ever were put in to commercial production. They submerged who boards in to it and then supercooled the fluid. I don't remember the chemical names. I do, but have no idea why. http://en.wikipedia.org/wiki/Perfluorohexane The fluid was a relative of Freon and held sufficient levels of oxygen to support lung breathers. They used to have a tank with a live mouse submerged in it bouncing around and seeming to have no trouble not choking or drowning. A variation of it was also researched as a blood substitute for some special medical needs. I don't know how far that went.I know it is not all fantasy because I saw the live mouse. I believe you. I saw a similar scene in a movie, so I already knew it had to be true. Bonus points for anyone that can add to this thread's collection of off-topic but semi-interesting trivia and name the movie. I didn't try the blood substitute. How do you save a drowning mouse? Use mouse to mouse resuscitation. Thanks, I'll be here all week. Try the veal instead. If the the freezer doesn't work I suggest finding an identical drive and replace the electronic board. Worked for many damaged drives. Regards, Sebastian Seidl ___ freebsd-questions@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to "freebsd-questions-unsubscr...@freebsd.org"
Re: hard disk failure - now what?
Gary Gatten wrote: > Naw, I don't recall the POST error exactly, but from what I remember it > couldn't find a boot device. Could've been the controller, but from > what I recall I swapped the drive (later) and all was good. I really > don't recall though - I could've put the "bad" drive in a good laptop > and fixed it that way - really don't recall details. Wish I could fix > some other problems by throwing them in a freezer! > Some try to solve their marital problems with a freezer... and an axe ;-) signature.asc Description: OpenPGP digital signature
