Re: raid question

[Alvin Oga <aoga@ns.Linux-Consulting.com>]

hi ya rudy


On Sun, 17 Aug 2003, Rudy Gevaert wrote:

> Hello,
> 
> I was wondering can I set up raid when a partition is mounted?
> e.g.  hda3 is /home and I want to set up raid1 with hdc3.  

you can do the "mirroring" ( raid1 ) of hda3 to hdc3

but if you expect to boot off hdc  when hda is removed, than it 
probably wont work

and more importantly partition type should be F3 ( linux-raid )  insted of
ext2 or ext3

> Can I run mkraid when hda3 is in use?  I would use the following
> raidtab:

no ...

you do mkraid /dev/md0  .. you do NOT format /dev/hda or /dev/hdc
individually  .. other than the initial fdisk if you even need to do
that

> raiddev /dev/md0
>         raid-level      1
>         nr-raid-disks   2
>         nr-spare-disks  0
>         chunk-size      4
>         persistent-superblock 0
>         device          /dev/hda3
>         raid-disk       0
>         device          /dev/hdc3
>         raid-disk       1

looks good
 
> Also, would I lose data?  When happens if I change the above order?

if you type the wrong commands ...
	- yes... you lose data on /dev/hda
 
order doesnt mean anything in the above

more software raid howto  ( converting from /dev/hda  to sw-raid )

	http://www.1U-Raid5.net/HowTo

c ya
alvin