Re: [linux-lvm] SoftRaid and LVM

[svetljo <galia st-peter stw uni-erlangen de>]

Hi again have you looked at the new How-to on sistina.com the one about 
lvm-1.0
it say that on raid devices there shouldn't be created filesystem
sou probably have to recreate the md and not format it

it would be nice if you could change the partitions id of the md-device 
but i don't now how to do it  you can't do it with fdisk, cfdisk or 
with some other of the comandline tools
i have done it on a software RAID-0 with a Mandrake tool diskdrake but 
with the new versions in their devel. distribution it doesn't work


and about a mirroring on one disk i'm not shure you can benefit much
as far i know mirroring is for two separate hard drives and not for 
partitions
/dev/hda1  and /dev/hda2 are on the same disk so if fmth hapens to the 
disk you can not restore

dou you plan to move your root directory over it ?






Thorsten Sauter wrote:

> Hi,
>
> sorry for these short description :-)!
>
> Currently I'm using kernel 2.4.9 with the raidtools-0.90.
> The md0 device is a simple RAID1-Mirroring between hda1 and hda2.
>
> If I create a simple vg over these two disks and one disk goes bad, all of
> my datas are lost, isn't it? So I think it would be a nice idee to create
> a simple, minimum safety, mirror array and active the lvm over this array.
> > From now on, I have the flexibilty from the lvm and the safety from the
> raid!?
>
> I've found some patches for older lvm version in the internet (google,
> ...) and a patch on this list from october last year. But all these
> patches (?) are for very old lvm versions (0.8x) so I tink they don't work
> on newer lvm-versions.
>
> The problem, as described below, is that I can't create a volume group on
> a md-device.
>
> Are these infos enought? I hope so.
>
> Between my to mails I've created a new "blank" md-device (no old datas, no
> old fdisk probs). But the problem is the same.
> The lvm-howto and the raid-howtos doens't provide any informations for
> interacting raid with lvm. :-(
>
> Thanks for your help!
>
> Thorsten Sauter
> viastore systems GmbH
>
>
> --
> Your mouse has moved.
> Windows NT must be restarted for the change to take effect.
> Reboot now?  [OK]
>
> On Tue, 4 Sep 2001, svetljo wrote:
>
> > Hi
> > where did you find this patches
> > and what do you wont to do
> >
> > what kind of software RAID do you wont to use
> > can you give us a bit more information
> >
> >
> >
> >
> >
> >
> > Thorsten Sauter wrote:
> >
> > > Hello LVM-Gurus,
> > >
> > > I would like to create a volume group based on an sofraid device
> > > (/dev/md0). I know, there are many emails about this topic, but I think no
> > > one has the solution for this. I have found some code-patches for older
> > > versions of the lvm for fix this problem. But, what is the current state
> > > in the new lvm-1.0.1-rc2 version.
> > >
> > > The following things I have made before:
> > > $ mkraid --realy-force /dev/md0
> > > $ mkreiserfs /dev/md0
> > > $ mount /dev/md0 /mnt
> > > -> so I think, the raid device is ok
> > >
> > > $ pvcreate /dev/md0
> > >
> > > > pvcreate -- device "/dev/md0" has a partition table
> > > $ fdisk -l /dev/md0
> > >
> > > > Disk /dev/md0: 2 heads, 4 sectors, 2441880 cylinders
> > > > Units = cylinders of 8 * 512 bytes
> > > >
> > > >   Device Boot    Start       End    Blocks   Id  System
> > > $ uname -a
> > >
> > > > Linux lxclust1 2.4.9 #6 Mon Jan 3 19:52:54 CET 2000 i686 unknown
> > > $ dmesg | grep -i lvm
> > >
> > > > LVM version 0.9.1_beta2  by Heinz Mauelshagen  (18/01/2001)
> > > > lvm -- Driver successfully initialized
> > > LVM-Version: 1.0.1-rc2      -> why is this an other version as reported
> > > by kernel?
> > >
> > > Does anyone know, how can I initialize the /dev/md0 device for te the lvm?
> > >
> > > Thanks for your help,
> > >
> > > Thorsten Sauter
> > > viastore systems GmbH
> > >
> > >
> > > --
> > > Your mouse has moved.
> > > Windows NT must be restarted for the change to take effect.
> > > Reboot now?  [OK]
> > >
> > >
> > > _______________________________________________
> > > linux-lvm mailing list
> > > linux-lvm sistina com
> > > http://lists.sistina.com/mailman/listinfo/linux-lvm
> > > read the LVM HOW-TO at http://www.sistina.com/lvm/Pages/howto.html
> >
> >
> >
> > _______________________________________________
> > linux-lvm mailing list
> > linux-lvm sistina com
> > http://lists.sistina.com/mailman/listinfo/linux-lvm
> > read the LVM HOW-TO at http://www.sistina.com/lvm/Pages/howto.html
>
>
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