Hard Disk device IDs in Linux

Lonnie Olson lists at kittypee.com
Mon Mar 11 09:27:15 MDT 2013

On Mon, Mar 11, 2013 at 5:35 AM, Dan Egli <ddavidegli at gmail.com> wrote:
> Problem with LVM is it doesn't offer any failover protection that I am
> aware of. I admit I have not looked at lvm in some time, but last I looked
> the way it worked was as soon as any device in the group failed the entire
> group failed. And while it is possible (with some work) to recover the
> information from non-failed devices, the info that was on the failed device
> is lost forever (unless you have a good recent backup). That's why I was
> looking at using mdadm to create a RAID 6 or something. The combination of
> capacity is good, but I need the failover protection too.

No LVM doesn't provide any RAID protection itself.  It's not meant to,
it's just a volume manager.
You are supposed to layer it on top of RAID.  In you case you build
your RAID in md using mdadm just like normal, then add the resulting
block device to LVM as your Physical Volume.  That way you get all the
benefits of both RAID and LVM.

RAID -> LVM -> Filesystem

LVM can use any block device as a physical volume.  This includes
whole disks, partitions, iSCSI, files, etc.

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