On 3-Feb-08, at 10:52 PM, Maximo Ramos wrote:
Hello there!!
One of my hard disks just died, and it messed up my LVM setup.
My LVM Setup (LVM partitions: 1, 2 and 3):
Disk 1 = root particion and LVM 3
Disk 2 = LVM 1
Disk 3 = LVM 2
Disk 1 is dead, and with it, the /etc/lvm folder with all the
information regarding my LVM setup. My research about recovering LVM
setups involves having access to the /etc/lvm folder and hacking it,
which is not my case.
Which kernel/lvm release?
IRC, LVM2 should have on-disk metadata associated with each PV
including volume group (VG) definitions and LVs. Did you have a
logical volume spanning multiple disks, or just volumes on each
physical disk?
The first question in this case would be: should you first use RAID?
But some sites, may have choose these types of arrangements on LVM w/
o RAID due to existing configuration, site policy, predicted disk
load/space utilization, etc.
There was a really good presentation back in 2004-2005 timeframe at
OCLUG regarding LVM. Thanks again to the presenter. Also the
O'Reilly book: "Managing RAID on Linux" covers multiple disk
volumes / partitioning arrangements.
Links:
* http://en.wikipedia.org/wiki/Logical_volume_management
* http://www.linuxdevcenter.com/pub/a/linux/2006/04/27/managing-disk-
space-with-lvm.html
* http://www.oreilly.com/catalog/mraidlinux/
* http://sources.redhat.com/lvm2/
An example topology might include:
hda [PV1 (VG1 LV1 {LV2} ) ]
hdb [PV2 (VG1 LV3 {LV2} )(VG2 {LV4} ) ]
hdc [PV3 (VG2 {LV4} LV5 ) ]
in which case if hda dies, PV1 is gone and half of VG1 is toast, but
PV{2,3} are around and thus you can still access VG2 and associated:
LV4 and LV5. The question is how easy is it to access LV3 (valid
file system) and the remainder of LV2 (partial/broken FS). I've
never ran into a situation where LVM VGs were part accessible if that
is the situation. That would be a good test case for LVM2 Utilities.
I just installed a new hard disk (new Disk 1) with a fresh install of
Fedora. Is there any way to -at least- recover the information in my
LVM setup (Disk 2 and 3), always taking into account that I don't have
the original /etc/lvm folder, not even in backups.
You may be able to use a Linux livecd and use the pvscan, vgscan and
lvscan tools. The lvm interactive CLI is included with most modern
distributions.
Thanks for your attention.
Maximo
Allan Fields <afields [ at ] ncf [ dot ] ca>