[Gllug] RAID 1 and RAID 5

[Xander D Harkness]

David Irvine wrote:
> On Wed, 2002-12-04 at 16:00, Andrew Halliwell wrote:
> 
>>>i'm assuming you're speaking about a HW solution?
>>
>>Looks like software to me... He mentioned /etc/raidtab after all.
>>
> 
> This is just theory, but... Raid 1=2 disks mirrored. Raid 5=3 or more
> disks with parity.
> 
> At present you have raid 1.
I did not know whether the kernel did a different format on the raid 
devices for raid 1 and raid 5.

While I realise that I will have no more than raid 1 with two devices.

I think that I have already started on the degraded raid 5 array.  I 
have a conflicting raid 5 / raid 1 set up.

The raidtab states raid 5 but only has two disks.  Does the kernel set 
it up for degraded raid 5 or does it set it up for raid 1 and ignore the 
raid level in the raidtab file?

If the raid 1 and 5 devices are not different I should be able to add 
another disk to the current setup.

I shall find out in a bit when I have finished copying the 120Gb across 
to free the disk :-)

Kind regards
Xander
> 
> if you pull out disk two from your raid 1 setup, you have 1 working disk
> with your data.
> if you then put two new disks in you now still have your raid1 setup,
> plus 2 disks which is enough to make a failed 3 disk raid5 array
> 
> so if you then mkraid? the two disks it should make a degraded raid5
> disk array.
> 
> If that works you can copy your raid 1 data onto your raid5 array and
> then take disk1 out of the raid1 array (killing it) delete the raid1
> array, then put the disk back in and tell the raid5 array this is the
> new replacement disk.
> 
> I've not tried this but dont see why it wouldnt work.
> 
> David
> 
> 
> If you have a 
> 
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