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s2cuts 01-22-2008 01:40 AM

LVM, what happens with a drive falure?
Quick question. If I have say two physical volumes from different disks as part of a single logical volume, would the failure of one of those disks cause the data on the other physical volume to become inaccessible? Would there be a method to at least recover the data off of the good disk?

I'm just trying to wrap my head comfortably around LVM before I implement it.

trickykid 01-22-2008 10:41 AM

You could lose data. That's the drawback. If you want to save yourself the hassle of potential drive failure, implement a RAID solution. Means more disks but is your data worth it?

s2cuts 01-22-2008 12:31 PM

Mirroring aside, I want to understand how LVM copes with the loss of a disk. For example, if a disk that was only part of a logical volume were to fail, would the LV still be partially accessible after the failure?

I quess this is part of the answer to my question: Logical Volume Manager (Linux) from Wikipedia
"...LVM keeps a metadata header at the start of every PV, each of which is uniquely identified by a UUID. Each PV's header is a complete copy of the entire volume group's layout, including the UUIDs of all other PV, the UUIDs of all logical volumes and an allocation map of PEs to LEs. This simplifies data recovery in the event of PV loss..."

trickykid 01-22-2008 12:42 PM

Yes, if you have two drives with LVM spread across both as one logical volume, if one drive fails, you should be able to recover the data from the good drive.

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