Question about LVM and RAID

[Gilboa Davara]

On Thu, 2007-11-29 at 11:54 -0500, Kanwar Ranbir Sandhu wrote:
> Hi All,
> 
> I have an external drive cage which has been configured with two
> separate RAID 5 arrays.  I then used LVM to create two PVs, and then
> added the volumes together under one VG.  The whole shebang is mounted
> on one file system (/srv).

Ouch... Bad configuration.
If you're looking for two dead disk support, test the Linux' kernel
software RAID6 support.

> 
> What would happen if one of the RAID arrays failed (e.g. two drives die
> in RAID 5 array 1)?  Would the data be safe, would I lose all data, or
> would I just lose the data that was on the failed array?

Two drives in either RAID will most likely kill your LVM.

> 
> I believe I would only lose the data on the failed array, but a friend
> believe I would lose the whole lot.


It's a matter of blind luck, but any LV that sits on the dead RAID5
array will be taken with it.

- Gilboa