Question about LVM and RAID

rainer rainer at
Thu Nov 29 17:05:29 UTC 2007


I suppose you have only made a JBOD with LVM - no further RAID0 or such.

With JBOD, at least the data on the left RAID5-set should be safe. The 
data on the failed array and the bits and pieces which were on both 
arrays would be lost. Fragmentation and the size of data could be an 
issue - e.g. a 200 GB file on 2 x 160GB arrays would mean more than half 
is lost... ;(

I think your friend meant you had made a RAID0 above the RAID5-sets, 
which would indeed mean the whole thing would be lost.


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).
> 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?
> I believe I would only lose the data on the failed array, but a friend
> believe I would lose the whole lot.
> Thanks in advance!
> Regards,
> Ranbir

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