Re: [linux-lvm] Disk crash on LVM

[Ray Morris <support@bettercgi.com>]

   Here's one approach.

   pvmove is very slow and very safe.  You want 
to get the data off that drive in a hurry, before 
it heats up, so pvmove is not your friend in this 
case.  Freeze the drive, then find out which LVs 
are on it:
pvmove -m /dev/sdc1

  Hopefully, the drive contains whole LVs, or nearly 
whole, as opposed to having just little portions of 
many LVs. If most of the LV is on sdc1, we're going 
to use dd to get the data off before the drive gets 
too warm.  For small portions of larger LVs, you can 
use pvmove.  

   To prepare for the dd, create a new VG that doesn't
use sdc2.  Then use lvdisplay and lvcreate -l to create 
duplicate LVs:
lvcreate -n something -l sameextents copy

   Then dd from the old copy of the LV to the new:

dd if=/dev/org/$1 bs=64M iflag=direct | 
dd of=/dev/copy/$1 bs=64M oflag=direct 

   That piped dd is 2-3 times faster than the "obvious" 
way to run dd.

   It might also make sense to just dd the whole drive
instead of doing on LV at a time.
--
Ray Morris
support@bettercgi.com

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On 09/18/2009 03:47:26 PM, Fredrik Skog wrote:
> Hi
> 
> I'm a beginner with LVM2. I run Gentoo Linux with a LV consisting och
> 5 
> physical drives. I use LVM2 as it's installed so i guess it's not
> striped. 
> It started out with read problems of the drive at certain times, it
> took a 
> long time to access files. I then used smartctl to test the drive and
> it 
> reported a failure.
> 
> ID# ATTRIBUTE_NAME          FLAG     VALUE WORST THRESH TYPE     
> UPDATED 
> WHEN_FAILED RAW_VALUE
>   1 Raw_Read_Error_Rate     0x000f   200   200   051    Pre-fail 
> s       -       1453
>   3 Spin_Up_Time            0x0003   148   148   021    Pre-fail 
> s       -       7591
>   4 Start_Stop_Count        0x0032   100   100   000    Old_age 
> ys       -       38
>   5 Reallocated_Sector_Ct   0x0033   126   126   140    Pre-fail 
> Always 
> FAILING_NOW 591
>   7 Seek_Error_Rate         0x000e   200   200   051    Old_age 
> ys       -       0
> ....
> ...
> 
> I shut down the whole system and bought a new drive and added to the
> VG. 
> When the failed drive is cold it's regognized by LVM when i boot, but
> if it 
> gets warm it's not even recognized. a pvs results in this
> 
> # pvs
>   /dev/sdc: read failed after 0 of 4096 at 0: Input/output error
>   /dev/sdc1: read failed after 0 of 2048 at 0: Input/output error
>   /dev/block/253:0: read failed after 0 of 4096 at 500103577600: 
> Input/output error
>   /dev/block/253:0: read failed after 0 of 4096 at 500103634944: 
> Input/output error
>   /dev/sdc: read failed after 0 of 4096 at 0: Input/output error
>   /dev/sdc: read failed after 0 of 4096 at 500107771904: Input/output
> error
>   /dev/sdc: read failed after 0 of 4096 at 500107853824: Input/output
> error
>   /dev/sdc: read failed after 0 of 4096 at 0: Input/output error
>   /dev/sdc: read failed after 0 of 4096 at 4096: Input/output error
>   /dev/sdc: read failed after 0 of 4096 at 0: Input/output error
>   /dev/sdc1: read failed after 0 of 1024 at 500105150464: Input/
> output
> error
>   /dev/sdc1: read failed after 0 of 1024 at 500105207808: Input/
> output
> error
>   /dev/sdc1: read failed after 0 of 1024 at 0: Input/output error
>   PV         VG    Fmt  Attr PSize   PFree
>   /dev/hda1  vgftp lvm2 a-    74.51G      0
>   /dev/hda2  vgftp lvm2 a-    74.51G      0
>   /dev/hda3  vgftp lvm2 a-    74.51G      0
>   /dev/hda4  vgftp lvm2 a-    74.55G      0
>   /dev/hdb1  vgftp lvm2 a-    74.51G      0
>   /dev/hdb2  vgftp lvm2 a-    74.51G      0
>   /dev/hdb3  vgftp lvm2 a-    74.51G      0
>   /dev/hdb4  vgftp lvm2 a-    74.55G      0
>   /dev/sdb1  vgftp lvm2 a-   931.51G      0
>   /dev/sdc1  vgftp lvm2 a-   465.76G      0
>   /dev/sdd1  vgftp lvm2 a-   931.51G      0
>   /dev/sde1  vgftp lvm2 a-     1.36T 931.50G
> 
> I want to do a pvmove from the old drive to my newly added drive, but
> as 
> soon as i do that i get the same error as when i do the pvs command.
> Maybe I 
> will try to freeze my drive if nothing else works. Is there a way to
> force 
> pvmove or somethin similiar? I really would like to rescue as much
> data as 
> possible from the failed drive.
> 
> If it's not possible to rescue anything from the drive. How should i
> proceed 
> for best results regarding the rest of the drives? Will i still be
> able to 
> access the files on the other drives?
> How do i remove the failed drive in a good maner? pvremove? vgreduce?
> 
> I couldn't seem to find any info on how to best remove a failed drive
> with 
> an accepted data loss.
> 
> thanks
> /Fredrik
> 
> 
> 
> 
> ----- Original Message ----- 
> From: "Milan Broz" <mbroz@redhat.com>
> To: "LVM general discussion and development" <linux-lvm@redhat.com>
> Sent: Friday, September 18, 2009 9:48 PM
> Subject: Re: [linux-lvm] Question on compatibility with 2.6.31 
> kernel.
> 
> 
> > Ben Greear wrote:
> >> I recently tried to boot 2.6.31 on Fedora 8, and it couldn't
> >> find the volume groups.  The same kernel works fine on F11.
> >
> > try to recompile kernel with
> > CONFIG_SYSFS_DEPRECATED=y
> > CONFIG_SYSFS_DEPRECATED_V2=y
> >
> > (old lvm will not understand new sysfs design, this should
> > provide old sysfs entries)
> >
> >> Someone on LKML said they had similar problems on an old Debian
> Etch
> >> system and to fix it they installed a new version of lvm2 and put
> >> that in the initrd.
> >
> > yes, this is another option, new lvm2 (I think >2.02.29) should
> work.
> > But note that also device-mapper library must be updated.
> >
> > Milan
> >
> > _______________________________________________
> > linux-lvm mailing list
> > linux-lvm@redhat.com
> > https://www.redhat.com/mailman/listinfo/linux-lvm
> > read the LVM HOW-TO at http://tldp.org/HOWTO/LVM-HOWTO/ 
> 
> _______________________________________________
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> linux-lvm@redhat.com
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> read the LVM HOW-TO at http://tldp.org/HOWTO/LVM-HOWTO/
> 
>