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echo6
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Joined: 04 Jan 2003
Posts: 587
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 Posted: Tue Aug 14, 2007 10:29 am Post subject: Accessing Duplicate LVM2 VolumeGroups |
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I removed a drive with LVM2 and re-installed another drive with LVM2.
I wish to access the volumes from the old drive and I'm using an external usb caddy. I have two duplicate VolumeGroup00 entries and I can see no way to access or rename the old VolumeGroup00
| Code: | lvm> vgscan
Reading all physical volumes. This may take a while...
WARNING: Duplicate VG name VolGroup00: Existing WSTzAK-sgEc-de0j-S2Ia-GMVd-Rv2k-y6VWbB (created here) takes precedence over p2qSKr-tMC3-2YPE-SoP9-mFFt-2oCA-gmmR4w
Found volume group "VolGroup00" using metadata type lvm2
Found volume group "VolGroup00" using metadata type lvm2
lvm> vgdisplay
--- Volume group ---
VG Name VolGroup00
System ID
Format lvm2
Metadata Areas 1
Metadata Sequence No 4
VG Access read/write
VG Status resizable
MAX LV 128
Cur LV 2
Open LV 2
Max PV 0
Cur PV 1
Act PV 1
VG Size 24.69 GB
PE Size 32.00 MB
Total PE 790
Alloc PE / Size 789 / 24.66 GB
Free PE / Size 1 / 32.00 MB
VG UUID p2qSKr-tMC3-2YPE-SoP9-mFFt-2oCA-gmmR4w
--- Volume group ---
VG Name VolGroup00
System ID
Format lvm2
Metadata Areas 1
Metadata Sequence No 4
VG Access read/write
VG Status resizable
MAX LV 128
Cur LV 2
Open LV 2
Max PV 0
Cur PV 1
Act PV 1
VG Size 43.12 GB
PE Size 32.00 MB
Total PE 1380
Alloc PE / Size 1379 / 43.09 GB
Free PE / Size 1 / 32.00 MB
VG UUID WSTzAK-sgEc-de0j-S2Ia-GMVd-Rv2k-y6VWbB |
Suggestions? |
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Janne Pikkarainen
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Joined: 29 Jul 2003
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Location: Helsinki, Finland
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| Posted: Tue Aug 14, 2007 11:12 am Post subject: |
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man vgrename.
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echo6
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Posts: 587
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| Posted: Tue Aug 14, 2007 12:17 pm Post subject: |
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| Yes I appreciate there is a man page for the lvm tools. Although when I try to do that it suggests I need to distinguish between them using UUID but the man page or the vgrename tool gives no hint how this is achieved. |
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Janne Pikkarainen
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Joined: 29 Jul 2003
Posts: 1143
Location: Helsinki, Finland
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| Posted: Tue Aug 14, 2007 12:28 pm Post subject: |
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Oh, sorry, should have been more verbose.  What if you try
| Code: | | vgrename /dev/disk/by-uuid/your_another_uuid some_other_name |
(try that with your own responsibility, I've actually not done that before!)
... or unplug the other drive, rename the volume group and then plug in the another drive again?
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echo6
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| Posted: Tue Aug 14, 2007 2:27 pm Post subject: |
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Again that would be ok but /dev/disk/by-uuid doesn't contain VG UUIDs.
Although the vgrename hints at using uuid there appears to be no way of it handling them.
There appears to be a gap here in the userspace utils for LVM2!
Oh! btw I removed the new drive replaced with the old and then booted with a livecd to rename the VolGroup00 to VG00, now it's lost my volumes LOL. |
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manaka
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Joined: 23 Jul 2007
Posts: 178
Location: Spain
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| Posted: Tue Aug 14, 2007 2:46 pm Post subject: |
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I faced a similar problem some time ago. I used the method described in http://www.linuxjournal.com/node/8874/print. It worked for me.
Basically the trick is to use vgcfgrestore to rewrite the volume group name.
Good luck...
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Javier Miqueleiz
"Listen to your heart. It knows all things, because it came from the Soul of the World, and it will one day return there." |
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echo6
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| Posted: Tue Aug 14, 2007 3:13 pm Post subject: |
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Thanks for the link to the article.
Looks like having lost the metadata to the old drive I've lost the volumes, which were only swap and / fortunately I had made a backup of the data before hand.
I'm still concerned that there appears to be no means of handling Volume Group names where they are identical even though a VG UUID exists which could provide a mechanism to handle this situation. |
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manaka
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Location: Spain
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| Posted: Wed Aug 15, 2007 5:48 am Post subject: |
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Yes... The VG UUID could be used to differentiate between 2 VGs with the same name.
But you would have a device names issue. If both VGs have a LV named "root", how should the devices be named?
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Javier Miqueleiz
"Listen to your heart. It knows all things, because it came from the Soul of the World, and it will one day return there." |
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echo6
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| Posted: Wed Aug 15, 2007 6:15 am Post subject: |
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| manaka wrote: | | If both VGs have a LV named "root", how should the devices be named? |
Surely that shouldn't be an issue.
e.g. If I have a VolGroup00 with a VG uuid of p2qSKr-tMC3-2YPE-SoP9-mFFt-2oCA-gmmR4w and
VolGroup00 with a VG uuid of WSTzAK-sgEc-de0j-S2Ia-GMVd-Rv2k-y6VWbB
Then the could appear as /dev/mapper/VolGroup00-p2qSKr-tMC3-2YPE-SoP9-mFFt-2oCA-gmmR4w and
/dev/mapper/VolGroup00-WSTzAK-sgEc-de0j-S2Ia-GMVd-Rv2k-y6VWbB and so on and according to the LVM metadata each of the logical volumes also have uuids. |
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manaka
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Joined: 23 Jul 2007
Posts: 178
Location: Spain
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| Posted: Wed Aug 15, 2007 11:53 am Post subject: |
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Well... I meant it was an issue from a user/system administratror view... The device names would become rather unfriendly...
But as you point out, it could be done, of course... 
_________________
Javier Miqueleiz
"Listen to your heart. It knows all things, because it came from the Soul of the World, and it will one day return there." |
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