* [linux-lvm] accidently formatted a physical volume... @ 2002-08-19 14:23 Adam McDaniel 2002-08-19 14:38 ` Steven Lembark 0 siblings, 1 reply; 8+ messages in thread From: Adam McDaniel @ 2002-08-19 14:23 UTC (permalink / raw) To: linux-lvm [-- Attachment #1: Type: text/plain, Size: 896 bytes --] Hi.. I've had a simple implementation of LVM running on two 10gig harddrives.. Everything was working fine until one day a co-worker decided he wanted to run `mkfs.ext2 /dev/hdb` Needless to say, the VG was screwed and I couldn't get any data out. My question is that I'm wondering if there is any way I can salvage the other PV and alteast get SOME data out. Or, is there any way that I can fix/restore the formatted drive? For some background info, I had one VG, two PVs, and one LV with ext2 running on it. I *believe* I had it configured to concatinate the data, but im not 100% if it was setup in stripe mode. I'm running LVM 1.0.0-3 (debian/testing) Sorry if this question has been asked before, I tried searching through the mailing-list/howto for an answer but found nothing useful. Thanks in advance :) -- Adam McDaniel Array Networks Calgary, AB, Canada [-- Attachment #2: Type: application/pgp-signature, Size: 232 bytes --] ^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [linux-lvm] accidently formatted a physical volume... 2002-08-19 14:23 [linux-lvm] accidently formatted a physical volume Adam McDaniel @ 2002-08-19 14:38 ` Steven Lembark [not found] ` <284650000.1029786116@[192\.168\.200\.4]> 0 siblings, 1 reply; 8+ messages in thread From: Steven Lembark @ 2002-08-19 14:38 UTC (permalink / raw) To: linux-lvm > Or, is there any way that I can fix/restore the formatted drive? Not at the *NIX level. If the data were SERIOUSLY valuable it can be recovered by physical means. Short of that I'd say it's time to reach for your tapes... -- Steven Lembark 2930 W. Palmer Workhorse Computing Chicago, IL 60647 +1 800 762 1582 ^ permalink raw reply [flat|nested] 8+ messages in thread
[parent not found: <284650000.1029786116@[192\.168\.200\.4]>]
* Re: [linux-lvm] accidently formatted a physical volume... [not found] ` <284650000.1029786116@[192\.168\.200\.4]> @ 2002-08-19 15:42 ` Anders Widman 2002-08-19 15:50 ` Adam McDaniel 0 siblings, 1 reply; 8+ messages in thread From: Anders Widman @ 2002-08-19 15:42 UTC (permalink / raw) To: Steven Lembark >> Or, is there any way that I can fix/restore the formatted drive? > Not at the *NIX level. If the data were SERIOUSLY valuable > it can be recovered by physical means. Short of that I'd > say it's time to reach for your tapes... Are you sure? The data should be there in the co-worker did not make a "full" (zeroing blocks) format. Is it not possible to restore the LVM headers (or what it is called) on that drive? - Anders > -- > Steven Lembark 2930 W. Palmer > Workhorse Computing Chicago, IL 60647 > +1 800 762 1582 > _______________________________________________ > linux-lvm mailing list > linux-lvm@sistina.com > http://lists.sistina.com/mailman/listinfo/linux-lvm > read the LVM HOW-TO at http://www.sistina.com/lvm/Pages/howto.html ^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [linux-lvm] accidently formatted a physical volume... 2002-08-19 15:42 ` Anders Widman @ 2002-08-19 15:50 ` Adam McDaniel 2002-08-19 15:58 ` Kirby C. Bohling 0 siblings, 1 reply; 8+ messages in thread From: Adam McDaniel @ 2002-08-19 15:50 UTC (permalink / raw) To: linux-lvm [-- Attachment #1: Type: text/plain, Size: 1039 bytes --] On Mon, Aug 19, 2002 at 10:41:24PM +0200, Anders Widman wrote: > > >> Or, is there any way that I can fix/restore the formatted drive? > > > Not at the *NIX level. If the data were SERIOUSLY valuable > > it can be recovered by physical means. Short of that I'd > > say it's time to reach for your tapes... The unfortunate thing was that timing couldn't have been worse. The last backup I made before the incident would only contain a fraction of the info that I actually need. Partly my fault, I know, but being able to restore the drive would be the goal. > Are you sure? The data should be there in the co-worker did not make a > "full" (zeroing blocks) format. Is it not possible to restore the LVM > headers (or what it is called) on that drive? I do know that it was a straight simple format, literally 'mkfs.ext2 /dev/hdb', so I know the info is still there. My experience in this is rather limited, so I'm not sure of the best way to fish it out. -- Adam McDaniel Array Networks Calgary, AB, Canada [-- Attachment #2: Type: application/pgp-signature, Size: 232 bytes --] ^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [linux-lvm] accidently formatted a physical volume... 2002-08-19 15:50 ` Adam McDaniel @ 2002-08-19 15:58 ` Kirby C. Bohling 2002-08-20 12:56 ` Adam McDaniel 0 siblings, 1 reply; 8+ messages in thread From: Kirby C. Bohling @ 2002-08-19 15:58 UTC (permalink / raw) To: linux-lvm Start by using dd or something to get an original image of the drive before anything else bad is done to it. Copy it off to another drive, copy to tape. Personally, I'd copy it to a big filesystem (if it supports bigger then 2 GB), and see if you can mount it loopback. I know I read on the LKML a guy mounted several filesytems that way that were considerablely larger then 2GB. With the backup, when something goes wrong you can always start over fresh without worring about the undoing your original attempts. I'd imagine that doing a vgcfgrestore to the device, followed by mounting the filesystem without fsck'ing it will get you some data. Running fsck on it afterwards and see what else you can get. Do *_NOT_* try that without a backup of the original media. Your big problem is that you're going to have superblocks and inode tables written right in the middle of your drive other then that, everything should be on the disk right where you left it. I had a friend who just lost an ext2 drive due to a power surge the other day, fscking it was destorying the filesystem, just mounting it and running tar got us 90% of the data. Fortuantely the other 10% came off a RH CD so it was no problem. Thanks, Kirby Adam McDaniel wrote: > On Mon, Aug 19, 2002 at 10:41:24PM +0200, Anders Widman wrote: > >>>>Or, is there any way that I can fix/restore the formatted drive? >>> >>>Not at the *NIX level. If the data were SERIOUSLY valuable >>>it can be recovered by physical means. Short of that I'd >>>say it's time to reach for your tapes... >> > > The unfortunate thing was that timing couldn't have been worse. The > last backup I made before the incident would only contain a fraction > of the info that I actually need. Partly my fault, I know, but being > able to restore the drive would be the goal. > > >>Are you sure? The data should be there in the co-worker did not make a >>"full" (zeroing blocks) format. Is it not possible to restore the LVM >>headers (or what it is called) on that drive? > > > I do know that it was a straight simple format, literally > 'mkfs.ext2 /dev/hdb', so I know the info is still there. My experience > in this is rather limited, so I'm not sure of the best way to fish it > out. > ^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [linux-lvm] accidently formatted a physical volume... 2002-08-19 15:58 ` Kirby C. Bohling @ 2002-08-20 12:56 ` Adam McDaniel 2002-08-20 13:29 ` Kirby C. Bohling 0 siblings, 1 reply; 8+ messages in thread From: Adam McDaniel @ 2002-08-20 12:56 UTC (permalink / raw) To: linux-lvm [-- Attachment #1: Type: text/plain, Size: 2732 bytes --] On Mon, Aug 19, 2002 at 03:49:46PM -0500, Kirby C. Bohling wrote: > I'd imagine that doing a vgcfgrestore to the device, followed by > mounting the filesystem without fsck'ing it will get you some data. Unfortunatly, I don't have any data for vgcfgrestore to build upon. Here's the current status: /dev/loop0 is pointing to /root/lvm/hde1 /dev/loop1 is pointing to /root/lvm/hdf1 (built via 'dd if=/dev/hd?1 of=/root/lvm/hd?1') /dev/loop0 is the good image /dev/loop1 is the fubar'd one. pvdisplay /dev/loop0: --- PV Name /dev/loop0 VG Name data PV Size 14.31 GB [30009357 secs] / NOT usable 1.01 MB [LVM: 135 KB] PV# 2 PV Status available Allocatable yes (but full) Cur LV 1 PE Size (KByte) 4096 Total PE 3663 Free PE 0 Allocated PE 3663 PV UUID 3IRYim-Lpgb-2N1Y-6TPu-C8mZ-58hy-exlmBm --- pvdisplay /dev/loop1: --- PV Name /dev/loop1 VG Name data PV Size 9.44 GB [19792017 secs] / NOT usable 4.07 MB [LVM: 130 KB] PV# 1 PV Status available Allocatable yes (but full) Cur LV 1 PE Size (KByte) 4096 Total PE 2415 Free PE 0 Allocated PE 2415 PV UUID P7xAxa-J36q-2C8i-2vKc-5KJO-2tQ6-H3eGiz --- First I tried running pvscan: --- pvscan -- reading all physical volumes (this may take a while...) pvscan -- inactive PV "/dev/loop0" is associated to unknown VG "data" (run vgscan) pvscan -- inactive PV "/dev/loop1" is associated to unknown VG "data" (run vgscan) pvscan -- total: 2 [23.75 GB] / in use: 2 [23.75 GB] / in no VG: 0 [0] --- fair enough.. so I run vgscan -v: --- vgscan -- removing "/etc/lvmtab" and "/etc/lvmtab.d" vgscan -- creating empty "/etc/lvmtab" and "/etc/lvmtab.d" vgscan -- reading all physical volumes (this may take a while...) vgscan -- scanning for all active volume group(s) first vgscan -- reading data of volume group "data" from physical volume(s) vgscan -- ERROR "vg_read_with_pv_and_lv(): current PV" can't get data of volume group "data" from physical volume(s) vgscan -- "/etc/lvmtab" and "/etc/lvmtab.d" successfully created vgscan -- WARNING: This program does not do a VGDA backup of your volume group --- ofcourse /etc/lvmtab and /etc/lvmtab.d/* are all blank/empty. If anything, I'm just about at the point where the dead drive is a writeoff (/dev/loop1).. but I would like to try to salvage the data on /dev/loop0 Any ideas? Thanks. -- Adam McDaniel Array Networks Calgary, AB, Canada [-- Attachment #2: Type: application/pgp-signature, Size: 232 bytes --] ^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [linux-lvm] accidently formatted a physical volume... 2002-08-20 12:56 ` Adam McDaniel @ 2002-08-20 13:29 ` Kirby C. Bohling 2002-08-20 13:55 ` Andreas Dilger 0 siblings, 1 reply; 8+ messages in thread From: Kirby C. Bohling @ 2002-08-20 13:29 UTC (permalink / raw) To: linux-lvm Okay, now I'm completely out of my league, and I'm making this up as I go. The only way I'd now to salvage anything is to try and figure out the layout of the LVM and the physical extents, read them off into a big flat file and mount it loop on the loop back as extended two. Is there anyways to get pvscan to be incredibly verbose and list the starting offset, and ending offset on the physical disk for each physical extent? Essentially, write fsck.lvm/debug_lvm the parameters would be the lv you want to salvage, and the target location you want to write it to. The big trick will be identifying corrupt LVM metadata, and avoiding those blocks like the plauge. In the end, LVM is an abstraction for a block device. So I'd create a file and connect a loopback that was the same size as the LV. So pull a physical extent, figure out if it is associated with the lv you're recovering. Take the lv extent offset it is, and seek the extent size * logical extent number and write it to the loopback device. Throwing away the LVM metadata. Now, you can take this big pile of bits to an ext2/3 guru, and ask them how to glean as much data as possible out of it. If the LV was completely on one disk, it should just fsck and mount. Assuming you didn't specify the sizes, and do a lot of resizing of the LV's that should be the case. Possibly asking the ext2/3 guru what the holes should be filled in with, and put that there. I'd guess zero's. This trick should work on both sets of disks, but it'll be easier to pull off with known good meta-data. It'd be a big pile of work, but if the data is worth it you might try it. It's entirely possible this program exists and I'm unaware of it, but if it doesn't, somebody should take the time to write it for the current code. I don't know LVM and the metadata, and I'm too busy to figure it out... Sorry. Just think if you do it, you'll be famous... Thanks, Kirby Adam McDaniel wrote: > On Mon, Aug 19, 2002 at 03:49:46PM -0500, Kirby C. Bohling wrote: > >>I'd imagine that doing a vgcfgrestore to the device, followed by >>mounting the filesystem without fsck'ing it will get you some data. > > > Unfortunatly, I don't have any data for vgcfgrestore to build upon. > Here's the current status: > > /dev/loop0 is pointing to /root/lvm/hde1 > /dev/loop1 is pointing to /root/lvm/hdf1 > (built via 'dd if=/dev/hd?1 of=/root/lvm/hd?1') > > /dev/loop0 is the good image > /dev/loop1 is the fubar'd one. > > pvdisplay /dev/loop0: > > --- > PV Name /dev/loop0 > VG Name data > PV Size 14.31 GB [30009357 secs] / NOT usable 1.01 MB [LVM: 135 KB] > PV# 2 > PV Status available > Allocatable yes (but full) > Cur LV 1 > PE Size (KByte) 4096 > Total PE 3663 > Free PE 0 > Allocated PE 3663 > PV UUID 3IRYim-Lpgb-2N1Y-6TPu-C8mZ-58hy-exlmBm > --- > > pvdisplay /dev/loop1: > > --- > PV Name /dev/loop1 > VG Name data > PV Size 9.44 GB [19792017 secs] / NOT usable 4.07 MB [LVM: 130 KB] > PV# 1 > PV Status available > Allocatable yes (but full) > Cur LV 1 > PE Size (KByte) 4096 > Total PE 2415 > Free PE 0 > Allocated PE 2415 > PV UUID P7xAxa-J36q-2C8i-2vKc-5KJO-2tQ6-H3eGiz > --- > > First I tried running pvscan: > > --- > pvscan -- reading all physical volumes (this may take a while...) > pvscan -- inactive PV "/dev/loop0" is associated to unknown VG "data" (run vgscan) > pvscan -- inactive PV "/dev/loop1" is associated to unknown VG "data" (run vgscan) > pvscan -- total: 2 [23.75 GB] / in use: 2 [23.75 GB] / in no VG: 0 [0] > --- > > fair enough.. so I run vgscan -v: > > --- > vgscan -- removing "/etc/lvmtab" and "/etc/lvmtab.d" > vgscan -- creating empty "/etc/lvmtab" and "/etc/lvmtab.d" > vgscan -- reading all physical volumes (this may take a while...) > vgscan -- scanning for all active volume group(s) first > vgscan -- reading data of volume group "data" from physical volume(s) > vgscan -- ERROR "vg_read_with_pv_and_lv(): current PV" can't get data of volume group "data" from physical volume(s) > vgscan -- "/etc/lvmtab" and "/etc/lvmtab.d" successfully created > vgscan -- WARNING: This program does not do a VGDA backup of your volume group > --- > > ofcourse /etc/lvmtab and /etc/lvmtab.d/* are all blank/empty. > > If anything, I'm just about at the point where the dead drive is a > writeoff (/dev/loop1).. but I would like to try to salvage the data on > /dev/loop0 > > Any ideas? > > Thanks. > ^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [linux-lvm] accidently formatted a physical volume... 2002-08-20 13:29 ` Kirby C. Bohling @ 2002-08-20 13:55 ` Andreas Dilger 0 siblings, 0 replies; 8+ messages in thread From: Andreas Dilger @ 2002-08-20 13:55 UTC (permalink / raw) To: Kirby C. Bohling; +Cc: linux-lvm On Aug 20, 2002 13:20 -0500, Kirby C. Bohling wrote: > In the end, LVM is an abstraction for a block device. So I'd create > a file and connect a loopback that was the same size as the LV. So pull a > physical extent, figure out if it is associated with the lv you're > recovering. Take the lv extent offset it is, and seek the extent size * > logical extent number and write it to the loopback device. Throwing > away the LVM metadata. Now, you can take this big pile of bits to an > ext2/3 guru, and ask them how to glean as much data as possible out of > it. If the LV was completely on one disk, it should just fsck and > mount. Assuming you didn't specify the sizes, and do a lot of resizing > of the LV's that should be the case. Possibly asking the ext2/3 guru > what the holes should be filled in with, and put that there. I'd guess > zero's. This trick should work on both sets of disks, but it'll be > easier to pull off with known good meta-data. Run something like "gpart" or build the findsuper program in e2fsprogs/misc, which should give you a pretty good idea of where things are put on the disk. Cheers, Andreas -- Andreas Dilger http://www-mddsp.enel.ucalgary.ca/People/adilger/ http://sourceforge.net/projects/ext2resize/ ^ permalink raw reply [flat|nested] 8+ messages in thread
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2002-08-19 14:23 [linux-lvm] accidently formatted a physical volume Adam McDaniel
2002-08-19 14:38 ` Steven Lembark
[not found] ` <284650000.1029786116@[192\.168\.200\.4]>
2002-08-19 15:42 ` Anders Widman
2002-08-19 15:50 ` Adam McDaniel
2002-08-19 15:58 ` Kirby C. Bohling
2002-08-20 12:56 ` Adam McDaniel
2002-08-20 13:29 ` Kirby C. Bohling
2002-08-20 13:55 ` Andreas Dilger
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