[linux-lvm] Re: raid 1 on a single disk

[ptb lab it uc3m es (Peter T. Breuer)]

ashwin chaugule <ashwin chaugule gmail com> wrote:
>          Im trying to get RAID 1 working on a single disk. Can anyone
> tell me if thats possible ?

Yes, of course it is.

> Do I have to use LVM for that ?

No.

> So, far this is what i've understood ...
> Now.. I have a separate disk on which I want RAID 1.
> so I create one PV on that disk (/dev/hdd)

No you don't. LVM is not involved.

> create a logical vol grp.


No you don't. LVM is not involved.


> add 4 LV's , for four filesystems of the same type ...

No you don't. LVM is not involved.

> then in /etc/raidtab or whatever ..
> say that i have 4 disks and for each disk specify each LV partition ..

No you don't, since LVM is not involved.

> then mkraid /dev/md0 ...
> 
> Is this correct if I want data to be mirrored across all 4 partitions
> , using RAID 1 on a single disk ?

So, you are talking about a mirror with 4 components, all of them
partitions on the same disk?

Well, that's silly, but nothing stops you doing it. Just maek a raidtab
for the mirror and name the partitions as raid-disk components there.
The RAID howto or faq should tell you all you need to know, as should
the mananpage for the conf file or mdadm, or whatever ...

Peter