[linux-lvm] filesystem corruption...
Anders Widman
andewid at tnonline.net
Fri Mar 1 07:25:02 UTC 2002
> On Thu, Feb 28, 2002 at 10:07:03AM +0100, Anders Widman wrote:
>>
>> > On Thu, Feb 28, 2002 at 09:35:53AM +0100, Anders Widman wrote:
>> >>
>> >> >> On Wednesday, February 27, 2002 04:42:28 PM -0700 Andreas Dilger <adilger at clusterfs.com> wrote:
>> >>
>> >> >>> On Feb 27, 2002 23:36 +0100, Anders Widman wrote:
>> >> >>>> Unfortunatley, something went seriously wrong. I can't mount the disk
>> >> >>>> any more, or use reiserfsck. They (mount/reiserfsck) say there isn't
>> >> >>>> a valid filesystem on the device. Vgscan does however find all devices
>> >> >>>> and can activate the volume group, but reiserfsck doesn't work.
>> >> >>>>
>> >> >>>> What should I do to be able to save a s much data as possible?
>> >> >>>
>> >> >>> dd if=/dev/vg/lv of=/new/disk conv=sync,noerror
>> >>
>> >> >> Then we should be able to use debugreiserfs and reiserfsck to
>> >> >> find a copy of the super in the log, or just recreate it.
>> >>
>> >> >> -chris
>> >>
>> >> > So. How much space would this require on the 'new' disk? The same
>> >> > amount as the entire LV? If that is, it would be impossible (for me,
>> >> > economically) to do this.
>> >>
>> >> > The disk with bad blocks is 80GB, and I have a "spare" 80GB disk, but
>> >> > not more.
>> >>
>> >> > //Anders
>> >>
>> >> Oh, I forgot to ask how I can recover the filsystem
>> >> header/suprtblock.. What exactly is "dd if=/dev/vg/lv of=/new/disk
>> >> conv=sync,noerror" doing to the data, except copying it to the new
>> >> device?
>>
>> > It copies all it can read to another sane device so that youe don't loose
>> > more data if your drive turns worse.
>>
>> > After that, you want to use "reiserfsck --rebuild-sb /dev/vg/lv".
>>
>> Ok. Unfortunatley, I can't get enough storage to copy all data. Would
>> it be possible to just copy the data from the broken disk to a new,
> So /dev/vg/lv is bigger than that disk?
Yes, much bigger...
>> identical disk (I have a "spare" disk of the same model), and then
>> rebuild the filsystem?
> Well, then pvcreate the spare disk, add it to your VG and
> "pvmove -i /dev/BrokenDisk /dev/SaneDisk" data over.
Great. I remember reading something about this '-i' option on this
list before, just didn't remember. So this is as safe as use 'dd' to
move all data from the bad disk to the new disk?
> You need to have recent LVM 1.0.3 tools in order to use the -i option of
> pvmove, which ignores read errors and you need to patch liblvm.h with the
> following one to make pvmove work correctly.
> After that repair the filesystem in /dev/vg/lv.
This patch below is to add the support to ignore read errors?
> diff -u -B -r1.43 -r1.44
> --- LVM/tools/lib/liblvm.h 18 Feb 2002 16:37:18 -0000 1.43
> +++ LVM/tools/lib/liblvm.h 20 Feb 2002 10:49:14 -0000 1.44
> @@ -93,10 +93,10 @@
> #include <time.h>
> #include <limits.h>
> #ifdef _G_LSEEK64
> -int lseek64 ( unsigned int, unsigned long long, unsigned int);
> +loff_t lseek64 ( int, loff_t, int);
> #define llseek lseek64
> #else
> -int llseek ( unsigned int, unsigned long long, unsigned int);
> +loff_t llseek ( int, loff_t, int);
> #endif
> #include <sys/ioctl.h>
> @@ -130,7 +130,7 @@
> #define LVMTAB "/etc/lvmtab" /* LVM table of VGs */
> #define LVMTAB_DIR "/etc/lvmtab.d" /* storage dir VG data */
> #define LVMTAB_MINSIZE ( sizeof ( vg_t) + sizeof ( lv_t) + sizeof ( pv_t))
> -#define LVM_DEV "/dev/lvm"
> +#define LVM_DEV LVM_DIR_PREFIX "lvm"
> #define VG_BACKUP_DIR "/etc/lvmconf"
> #define DISK_NAME_LEN 8
> #define LV_MIN_NAME_LEN 5
And thanks again for your help!
//Anders
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