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Old 06-09-2012, 02:09 PM   #1
bitsofme
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recover lvm after lost system disk

Hi everyone,

During an upgrade a destroyed my boot disk and now can not access my LVM.
Originally I had 1 disk with my system files and a LVM spread over three disks for my home directory.

After I installed Fedora 17 on the system disk I am unable to restore my lvm (who new you need to back up a lvm config file)

I followed some blog posts and other information to create a config file.


Code:
# Generated by LVM2 version 2.02.95(2) (2012-03-06): Mon Jun  4 17:01:30 2012

contents = "Text Format Volume Group"
version = 1

description = ""

creation_host = "(none)"	# Linux (none) 3.3.4-5.fc17.x86_64 #1 SMP Mon May 7 17:29:34 UTC 2012 x86_64
creation_time = 1338829290	# Mon Jun  4 17:01:30 2012

vg_big {
	id = "OBZT6E-tzAO-v80A-kN38-R1Uo-3GRI-dXd4wj"
	seqno = 13
	format = "lvm2" # informational
	status = ["RESIZEABLE", "READ", "WRITE"]
	flags = []
	extent_size = 8192
	max_lv = 256
	max_pv = 256
	metadata_copies = 0

	physical_volumes {

		pv0 {
			id = "PCNHHY-LSvJ-jKbt-TXbN-tceZ-0GPe-tshRED"
			device = "/dev/sdb"

			status = ["ALLOCATABLE"]
			flags = []
			dev_size = 3907029168
			pe_start = 384
			pe_count = 476932
		}

		pv1 {
			id = "h8j1UC-Uckf-Ob3w-UTea-nUfT-JPWc-sVdjeF"
			device = "/dev/sdc"

			status = ["ALLOCATABLE"]
			flags = []
			dev_size = 3907029168
			pe_start = 384
			pe_count = 476932
		}

		pv2 {
			id = "Ixsun3-rGKx-0xWB-tqFK-RDYq-OuNR-qIj5sO"
			device = "/dev/sda"

			status = ["ALLOCATABLE"]
			flags = []
			dev_size = 3907029168
			pe_start = 2048
			pe_count = 476932
		}
	}

	logical_volumes {

		big	{
			id = "ptLLIA-nQhQ-JsBQ-wur0-fejd-wV4E-Xj1PyR"
			status = ["READ", "WRITE", "VISIBLE"]
			flags = []
			segment_count = 1

			segment1 {
				start_extent = 0
				extent_count = 953864

				type = "striped"
				stripe_count = 1
				stripe_size = 8

				stripes = [
					"pv0", 0,
					"pv2", 0
				]
			}
		}
	}
}
but when i tried vgconfigrestore with the -t for test and got

Test mode: Metadata will NOT be updated and volumes will not be (de)activated.
Couldn't find device with uuid PCNHHY-LSvJ-jKbt-TXbN-tceZ-0GPe-tshRED.
Couldn't find device with uuid Ixsun3-rGKx-0xWB-tqFK-RDYq-OuNR-qIj5sO.
Segment with extent 953864 in PV unknown device not found
Couldn't read all logical volumes for volume group vg_big.
Restore failed.

lvmdiskscan
/dev/sda [ 1.82 TiB]
/dev/vg_main/lv_swap [ 13.72 GiB]
/dev/vg_main/lv_root [ 50.00 GiB]
/dev/vg_main/lv_home [ 84.81 GiB]
/dev/sdb [ 1.82 TiB]
/dev/sdc [ 1.82 TiB] LVM physical volume
/dev/sdd1 [ 500.00 MiB]
/dev/sdd2 [ 148.56 GiB] LVM physical volume
5 disks
1 partition
1 LVM physical volume whole disk
1 LVM physical volume



[root@main uuid_fixer]# fdisk -l

Disk /dev/sda: 2000.4 GB, 2000398934016 bytes
255 heads, 63 sectors/track, 243201 cylinders, total 3907029168 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes


Disk /dev/sdb: 2000.4 GB, 2000398934016 bytes
255 heads, 63 sectors/track, 243201 cylinders, total 3907029168 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes


Disk /dev/sdc: 2000.4 GB, 2000398934016 bytes
255 heads, 63 sectors/track, 243201 cylinders, total 3907029168 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x2c33c642

Device Boot Start End Blocks Id System

Disk /dev/sdd: 160.0 GB, 160040803840 bytes
255 heads, 63 sectors/track, 19457 cylinders, total 312579695 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x000dd6fd

Device Boot Start End Blocks Id System
/dev/sdd1 * 2048 1026047 512000 83 Linux
/dev/sdd2 1026048 312578047 155776000 8e Linux LVM

Disk /dev/mapper/vg_main-lv_swap: 14.7 GB, 14730395648 bytes
255 heads, 63 sectors/track, 1790 cylinders, total 28770304 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes


Disk /dev/mapper/vg_main-lv_root: 53.7 GB, 53687091200 bytes
255 heads, 63 sectors/track, 6527 cylinders, total 104857600 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes


Disk /dev/mapper/vg_main-lv_home: 91.1 GB, 91066728448 bytes
255 heads, 63 sectors/track, 11071 cylinders, total 177864704 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes

My guess is I need to assign uuids to the disks but I am unsure how to do this?

Anyone know how to recover my lvm?

With thanks

Andrew
Last edited by bitsofme; 06-09-2012 at 02:10 PM.
 
Old 06-09-2012, 03:53 PM   #2
Ser Olmy
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What does vgscan report?
 
Old 06-09-2012, 04:39 PM   #3
bitsofme
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vgscan -P -v
Partial mode. Incomplete logical volumes will be processed.
Wiping cache of LVM-capable devices
Wiping internal VG cache
Reading all physical volumes. This may take a while...
Finding all volume groups
Finding volume group "vg_main"
Found volume group "vg_main" using metadata type lvm2

vg_main is what the reinstall created on my boot disk

the lvm gui sees /dev/sdc as an unallocated volume.
 
Old 06-09-2012, 04:47 PM   #4
Ser Olmy
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Is there a partition table on /dev/sdc? (fdisk -l /dev/sdc)

From where did you get the IDs in the config file you posted?
 
Old 06-09-2012, 10:07 PM   #5
syg00
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Even better, tell us what you did (decision you took, and why) to (re-)create that config.
Maybe give a link to those blogs that you followed.

Interesting that a pvscan (on boot) doesn't find the (presumably) full volume pvs.

This could be such a can of worms.
Quote:
(who new you need to back up a lvm config file)
I won't even comment on that except to refer you to my sigline. Are we also to assume you haven't backed up that multivolume /home ?.
 
Old 06-10-2012, 07:48 AM   #6
bitsofme
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Quote:
I won't even comment on that except to refer you to my sigline. Are we also to assume you haven't backed up that multivolume /home ?.
The data is available but it would be very very time consuming to restore.
I had a back up of /etc but the lvm/backup and the other folders in /etc/lvm folder were empty not sure if the lvm backup needs a command to create it.
Quote:
Even better, tell us what you did (decision you took, and why) to (re-)create that config.
Maybe give a link to those blogs that you followed.
I used http://www.howtoforge.com/recover_da...lvm_partitions the second part deals with recovering a lvm.
The lvm config was recovered from the dd command dd if=/dev/sdc bs=512 count=255 skip=1 of=/tmp/md0.txt.
I then used strings to extract the text from the file (see attached file)

Quote:
Is there a partition table on /dev/sdc? (fdisk -l /dev/sdc)
fdisk -l /dev/sdc

Disk /dev/sdc: 2000.4 GB, 2000398934016 bytes
255 heads, 63 sectors/track, 243201 cylinders, total 3907029168 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x2c33c642

Device Boot Start End Blocks Id System

Quote:
From where did you get the IDs in the config file you posted?
from the recovered configuration from the above dd command
Attached Files
File Type: txt sdctext.txt (35.0 KB, 18 views)
Last edited by bitsofme; 06-10-2012 at 07:52 AM.
 
Old 06-10-2012, 08:01 AM   #7
Ser Olmy
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Quote:
Originally Posted by bitsofme View Post
fdisk -l /dev/sdc

Disk /dev/sdc: 2000.4 GB, 2000398934016 bytes
255 heads, 63 sectors/track, 243201 cylinders, total 3907029168 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x2c33c642

Device Boot Start End Blocks Id System
So, no partition table. Back when you configured LVM, did you run pvcreate on the entire device??

Try blkid /dev/sdc. That ought to tell us something.
 
Old 06-10-2012, 12:21 PM   #8
bitsofme
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Quote:
Try blkid /dev/sdc. That ought to tell us something.
su -c "blkid /dev/sdc"
Password:
/dev/sdc: UUID="h8j1UC-Uckf-Ob3w-UTea-nUfT-JPWc-sVdjeF" TYPE="LVM2_member"


su -c "blkid"
Password:
/dev/sdc: UUID="h8j1UC-Uckf-Ob3w-UTea-nUfT-JPWc-sVdjeF" TYPE="LVM2_member"
/dev/mapper/vg_main-lv_swap: UUID="576e853f-1064-4b22-aaf1-89eca9111913" TYPE="swap"
/dev/mapper/vg_main-lv_root: LABEL="_Fedora-17-x86_6" UUID="61736f39-b25a-49a4-85cd-8eda8e8e9e64" TYPE="ext4"
/dev/mapper/vg_main-lv_home: UUID="baef8ad2-deda-4f0c-974c-a92638c2eeb9" TYPE="ext4"
/dev/sdd1: UUID="86f1da31-0a91-40c1-b151-8650e0d2a497" TYPE="ext4"
/dev/sdd2: UUID="92UeWo-GcG7-CDbL-d2gz-Zeri-sA0j-1re3rQ" TYPE="LVM2_member"
Last edited by bitsofme; 06-10-2012 at 12:32 PM. Reason: removed cdrom entries from output
 
Old 06-10-2012, 02:28 PM   #9
Ser Olmy
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Does pvscan detect /dev/sdc as a physical volume?
 
Old 06-10-2012, 04:12 PM   #10
bitsofme
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Quote:
Does pvscan detect /dev/sdc as a physical volume?
Code:
 pvscan 
  PV /dev/sdd2   VG vg_main         lvm2 [148.53 GiB / 0    free]
  PV /dev/sdc                       lvm2 [1.82 TiB]
  Total: 2 [1.96 TiB] / in use: 1 [148.53 GiB] / in no VG: 1 [1.82 TiB]
 
Old 06-10-2012, 04:39 PM   #11
Ser Olmy
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OK, /dev/sdc is a valid LVM physical volume, and pvscan is able to detect it.

Since vgscan does not find a volume group on /dev/sdc, one may reasonably conclude that the volume group configuration is damaged or missing. The recommended procedure for recovering a volume group is to use vgrestore, but that would require a backup of /etc/lvm/backup/<vg name>.

Looking at your attempt to manually build a config file, I see that you tried to add /dev/sdc to the volume group "vg_big", along with /dev/sda and /dev/sdb. That will not work, as /dev/sda and /dev/sdb are members of a different volume group, "vg_main".

If that config file is correct, the old volume "big" was striped across /dev/sda (pv2) and /dev/sdc (pv0). As the reinstall wiped /dev/sda, your only option is to restore from backups.
 
Old 06-10-2012, 05:08 PM   #12
jschiwal
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Could you look at /dev/sdb? The lvmdisk scan didn't recognise it as an LVM physical volume. Were sdb and sda assembled into a raid array as indicated by your reconstructed config in the first post?
Last edited by jschiwal; 06-10-2012 at 05:10 PM.
 
Old 06-10-2012, 05:52 PM   #13
bitsofme
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Quote:
Looking at your attempt to manually build a config file, I see that you tried to add /dev/sdc to the volume group "vg_big", along with /dev/sda and /dev/sdb. That will not work, as /dev/sda and /dev/sdb are members of a different volume group, "vg_main".
Originally I had two drives configured with a stripe but I removed the stripe and created a three disk group without a stripe it is possible that the old configuration was still on the disk.

If you look in the attached file I got from the dd command you can see some with and some without a stripe. I looked and found the most recent config (from the date in the header)and tried to build the config from that. It is possible that the vg was called vg_main1 or similar.

I have stripped out the following from the dd command
Code:
# Generated by LVM2 version 2.02.95(2) (2012-03-06): Mon Jun  4 17:01:30 2012
contents = "Text Format Volume Group"
version = 1
description = ""
creation_host = "(none)"	# Linux (none) 3.3.4-5.fc17.x86_64 #1 SMP Mon May 7 17:29:34 UTC 2012 x86_64
creation_time = 1338829290	# Mon Jun  4 17:01:30 2012
zAO-v80A-kN38-R1Uo-3GRI-dXd4wj"
seqno = 13
status = ["RESIZEABLE", "READ", "WRITE"]
flags = []
extent_size = 8192
max_lv = 256
max_pv = 256
metadata_copies = 0
physical_volumes {
pv0 {
id = "PCNHHY-LSvJ-jKbt-TXbN-tceZ-0GPe-tshRED"
device = "/dev/sdb"
status = ["ALLOCATABLE"]
flags = []
dev_size = 3907029168
pe_start = 384
pe_count = 476932
pv1 {
id = "h8j1UC-Uckf-Ob3w-UTea-nUfT-JPWc-sVdjeF"
device = "/dev/sdc"
status = ["ALLOCATABLE"]
flags = []
dev_size = 3907029168
pe_start = 384
pe_count = 476932
pv2 {
id = "Ixsun3-rGKx-0xWB-tqFK-RDYq-OuNR-qIj5sO"
device = "/dev/sda"
status = ["ALLOCATABLE"]
flags = []
dev_size = 3907029168
pe_start = 2048
pe_count = 476932
logical_volumes {
big {
id = "ptLLIA-nQhQ-JsBQ-wur0-fejd-wV4E-Xj1PyR"
status = ["READ", "WRITE", "VISIBLE"]
flags = []
segment_count = 1
segment1 {
start_extent = 0
extent_count = 953864
type = "striped"
stripe_count = 2
stripe_size = 8
stripes = [
"pv0", 0,
"pv1", 0
Last edited by bitsofme; 06-10-2012 at 05:56 PM.
 
Old 06-10-2012, 06:05 PM   #14
bitsofme
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Just had a look at the disks sda and sdb with the dd command I got the config from sdc and got much the same

Code:
# Generated by LVM2 version 2.02.95(2) (2012-03-06): Mon Jun  4 17:01:30 2012
contents = "Text Format Volume Group"
version = 1
description = ""
creation_host = "(none)"	# Linux (none) 3.3.4-5.fc17.x86_64 #1 SMP Mon May 7 17:29:34 UTC 2012 x86_64
creation_time = 1338829290	# Mon Jun  4 17:01:30 2012
pv2 {
id = "Ixsun3-rGKx-0xWB-tqFK-RDYq-OuNR-qIj5sO"
device = "/dev/sda"
status = ["ALLOCATABLE"]
flags = []
dev_size = 3907029168
pe_start = 2048
pe_count = 476932
logical_volumes {
big {
id = "ptLLIA-nQhQ-JsBQ-wur0-fejd-wV4E-Xj1PyR"
status = ["READ", "WRITE", "VISIBLE"]
flags = []
segment_count = 1
segment1 {
start_extent = 0
extent_count = 953864
type = "striped"
stripe_count = 2
stripe_size = 8
stripes = [
"pv0", 0,
"pv2", 0
# Generated by LVM2 version 2.02.73(2) (2010-09-18): Wed Apr 13 05:41:32 2011
contents = "Text Format Volume Group"
version = 1
description = ""
and from sdb
Code:
# Generated by LVM2 version 2.02.95(2) (2012-03-06): Mon Jun  4 17:01:30 2012
contents = "Text Format Volume Group"
version = 1
description = ""
creation_host = "(none)"	# Linux (none) 3.3.4-5.fc17.x86_64 #1 SMP Mon May 7 17:29:34 UTC 2012 x86_64
creation_time = 1338829290	# Mon Jun  4 17:01:30 2012
 07:06:44 UTC 2011 x86_64
creation_time = 1302633542	# Tue Apr 12 19:39:02 2011
BLE"]
flags = []
segment_count = 1
segment1 {
start_extent = 0
extent_count = 953864
type = "striped"
stripe_count = 2
stripe_size = 8
stripes = [
"pv0", 0,
"pv1", 0
Last edited by bitsofme; 06-10-2012 at 06:13 PM.
 
Old 06-10-2012, 11:57 PM   #15
syg00
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Quote:
Originally Posted by bitsofme View Post
I had a back up of /etc but the lvm/backup and the other folders in /etc/lvm folder were empty not sure if the lvm backup needs a command to create it.
My apologies - yes, vgcfgbackup needs to be run, then /etc/lvm backed up. On some other media.
 
  


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