Re: [Evms-devel] Possible to create a degraded RAID5 array with EVMS?

[Mike T. <mh...@us...>]

On Sat, 2005-11-26 at 14:42, James Lee wrote:
> Hi there,
> 
> I'm having some more trouble with getting EVMS and mdadm to play nicely 
> together (even after upgrading EVMS)...
> 
> The steps I'm taking are:
> 
> 1. Starting with an empty drive (wiped it by zero-filling the start and end 
> of drive to make sure there's no residual partition table information).  
> Create two logical partitions (/dev/sdb5 and /dev/sdb6).
> 
> 2. Use mdadm to create a degraded "3-drive" RAID5 array called /dev/md0: 
> "mdadm --create /dev/md0 --level=5 --raid-devices=3 /dev/sdb5 /dev/sdb6 
> missing".
> 
> 3. Start EVMS.  It correctly detects the degraded RAID5 array on /dev/md0.
> 
> 4. In EVMS, create 4 partitions on /dev/sdb, each one just over half the 
> size of the partitions in the RAID5 array.  Create two 2-drive RAID0 
> stripes, from these partitions.
> 
> 5. Add one of these RAID0 arrays to the RAID5 array.  Wait for it to resync. 
>   RAID5 array is now active and non-degraded.
> 
> 6. Create an EXT3 filesystem and bung some files on it.
> 
> 7. Everything working fine so far.  Now expand the RAID5 array with the 
> other RAID0 array.  This seems to work fine.  No data lost on the partition 
> and no errors.
> 
> 8. Reboot.  When next starting EVMS, I get the following errors:
> 

In theory, this should work!!! I will try your scenario to find out what
went wrong.

--
Mike T.