[linux-lvm] RAID+LVM

[linux-lvm] RAID+LVM

[David Corbin]

I have a debian system with LVM on top of a RAID.  Once up and running, 
it seems to work OK.  It's the getting it up and running that's a 
problem.  At boot, the raid drive is started, and then

                /sbin/vgscan --verbose >/root/vg.start
                /sbin/vgchange -a y --verbose >>/root/vg.start

This yields :
----vg.start----
vgscan -- removing "/etc/lvmtab" and "/etc/lvmtab.d"
vgscan -- creating empty "/etc/lvmtab" and "/etc/lvmtab.d"
vgscan -- reading all physical volumes (this may take a while...)
vgscan -- "/etc/lvmtab" and "/etc/lvmtab.d" successfully created
vgscan -- WARNING: This program does not do a VGDA backup of your volume 
group

vgchange -- locking logical volume manager
vgchange -- finding all volume group(s)
vgchange -- no volume groups found
----end----

Now, after the system finishes booting, if login as root and run those 
two commands again, I get.


----vg.start----
vgscan -- removing "/etc/lvmtab" and "/etc/lvmtab.d"
vgscan -- creating empty "/etc/lvmtab" and "/etc/lvmtab.d"
vgscan -- reading all physical volumes (this may take a while...)
vgscan -- scanning for all active volume group(s) first
vgscan -- reading data of volume group "vg0" from physical volume(s)
vgscan -- found inactive volume group "vg0"
vgscan -- getting block device numbers for logical volumes

vgscan -- checking block device numbers of logical volumes

vgscan -- inserting "vg0" into lvmtab
vgscan -- backing up volume group "vg0"
vgscan -- checking volume group name "vg0"
vgscan -- checking volume group consistency of "vg0"
vgscan -- checking existence of "/etc/lvmtab.d"
vgscan -- storing volume group data of "vg0" in "/etc/lvmtab.d/vg0.tmp"
vgscan -- storing physical volume data of "vg0" in "/etc/lvmtab.d/vg0.tmp"
vgscan -- storing logical volume data of volume group "vg0" in 
"/etc/lvmtab.d/vg0.tmp"
vgscan -- renaming "/etc/lvmtab.d/vg0.tmp" to "/etc/lvmtab.d/vg0"
vgscan -- removing special files and directory for volume group "vg0"
vgscan -- creating directory and group character special file for "vg0"
vgscan -- creating block device special files for vg0
vgscan -- "/etc/lvmtab" and "/etc/lvmtab.d" successfully created
vgscan -- WARNING: This program does not do a VGDA backup of your volume 
group

vgchange -- locking logical volume manager
vgchange -- finding all volume group(s)
vgchange -- checking volume group name "vg0"
vgchange -- checking existence of volume group "vg0"
vgchange -- reading volume group data for "vg0" from lvmtab
vgchange -- checking volume group consistency  of "vg0"
vgchange -- checking if all physical volumes of volume group "vg0" are 
available
vgchange -- creating VGDA for "vg0" in kernel
vgchange -- volume group "vg0" successfully activated

vgchange -- unlocking logical volume manager
----end----

and everything works.

Now, maybe this is a question better asked on the RAID list, but what's 
changing between the boot-time process  and later that suddenly makes 
the LVM stuff work?

David Corbin.

Re: [linux-lvm] RAID+LVM

[Jose Luis Domingo Lopez]

On Sunday, 24 November 2002, at 07:57:31 -0500,
David Corbin wrote:

> I have a debian system with LVM on top of a RAID.  Once up and running, 
> it seems to work OK.  It's the getting it up and running that's a 
> problem.  At boot, the raid drive is started, and then
> 
>                /sbin/vgscan --verbose >/root/vg.start
>                /sbin/vgchange -a y --verbose >>/root/vg.start
> 
> Now, after the system finishes booting, if login as root and run those 
> two commands again, I get.
> 
I suppose your problem is the boot scritps trying to initialize LVM and
software RAID in the wrong order (at least for your setup). To make a
LVM on top of software RAID work, you first need to activate software
RAID and then LVM.

Maybe in the boot sequence LVM is initialized first, and it fails. Then
it activates software RAID, which succeedes. After system startup you
just need to "vgchange -ay", and everything works ok.

Check /etc/rc2.d (runlevel 2 is typical for Debian), and see if
rearranging boot scripts helps.

Regards,

-- 
Jose Luis Domingo Lopez
Linux Registered User #189436     Debian Linux Woody (Linux 2.4.19-pre6aa1)

Re: [linux-lvm] RAID+LVM

[David Corbin]

Jose Luis Domingo Lopez wrote:

>On Sunday, 24 November 2002, at 07:57:31 -0500,
>David Corbin wrote:
>
>  
>
>>I have a debian system with LVM on top of a RAID.  Once up and running, 
>>it seems to work OK.  It's the getting it up and running that's a 
>>problem.  At boot, the raid drive is started, and then
>>
>>               /sbin/vgscan --verbose >/root/vg.start
>>               /sbin/vgchange -a y --verbose >>/root/vg.start
>>
>>Now, after the system finishes booting, if login as root and run those 
>>two commands again, I get.
>>
>>    
>>
>I suppose your problem is the boot scritps trying to initialize LVM and
>software RAID in the wrong order (at least for your setup). To make a
>LVM on top of software RAID work, you first need to activate software
>RAID and then LVM.
>
>Maybe in the boot sequence LVM is initialized first, and it fails. Then
>it activates software RAID, which succeedes. After system startup you
>just need to "vgchange -ay", and everything works ok.
>
>Check /etc/rc2.d (runlevel 2 is typical for Debian), and see if
>rearranging boot scripts helps.
>  
>
I found the problem.  I had re-arrange the scripts in rc0.d to be 
correct, but not rcS.d.  Once they were in the correct order it works fine.

>Regards,
>
>  
>

[linux-lvm] RAID & LVM

[Info - Demerson]

Hullo, All...

I know it seems to be a very old question, but I can't find in the previous
messages, the answer for that..

Is it possible to use RAID and LVM together? If positive, is there a HOW-TO
telling something about it?

LVM will support mirroring someday?

Thanks in advance...

______________
Demerson Zounar
Analista de Suporte
demerson@zaffari.com.br

Re: [linux-lvm] RAID & LVM

[Svetoslav Slavtchev]

Quoting Info - Demerson <demerson@zaffari.com.br>:

> Hullo, All...
> 
> I know it seems to be a very old question, but I can't find in the
> previous
> messages, the answer for that..
> 
you create your raid devices, and then treat them as regular partitons from
which you want to create VG's and LV's, with the difference that you don't need
to change ( i think you cann't) their partition id to lvm ( 8e / 0x8e)

shortly :
mkraid /dev/md0 /dev/md1 /dev/md2 ...
pvcreate /dev/md0 /dev/md1 /dev/md2 ...
vgcreate  myVG /dev/md0 /dev/md1 /dev/md2 ...
....

> Is it possible to use RAID and LVM together?
no problems, a lot of people do use it
> If positive, is there a
> HOW-TO
> telling something about it?
> 
don't think so

good luck

svetljo

Re: [linux-lvm] RAID & LVM

[William Blunn]

> I know it seems to be a very old question, but I can't find in 
> the previous messages, the answer for that..
> 
> Is it possible to use RAID and LVM together? If positive, is 
> there a HOW-TO telling something about it?

Yes it works well.

Use the standard RAID stuff to make a raid device, say /dev/md0, then create a PV (LVM Physical Volume) on that, then make a VG (LVM volume group) out of that PV, then create LVs (LVM Logical Volumes) in the VG.

Then (unless you have some other use for them), create filesystems in the LVs.

I use LVM over RAID1 on ATA disks using Ultra-ATA mode 4 (66 MB/s) or higher.

> LVM will support mirroring someday?

Not AFAIK.

Bill
-- 
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Tao
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Re: [linux-lvm] RAID & LVM

[Heinz J . Mauelshagen]

On Tue, Jun 25, 2002 at 05:19:41PM +0100, William Blunn wrote:
> > I know it seems to be a very old question, but I can't find in 
> > the previous messages, the answer for that..
> > 
> > Is it possible to use RAID and LVM together? If positive, is 
> > there a HOW-TO telling something about it?
> 
> Yes it works well.
> 
> Use the standard RAID stuff to make a raid device, say /dev/md0, then create a PV (LVM Physical Volume) on that, then make a VG (LVM volume group) out of that PV, then create LVs (LVM Logical Volumes) in the VG.
> 
> Then (unless you have some other use for them), create filesystems in the LVs.
> 
> I use LVM over RAID1 on ATA disks using Ultra-ATA mode 4 (66 MB/s) or higher.
> 
> > LVM will support mirroring someday?

We've got a mirroring target already in device-mapper, which is the generic
volume mapping driver used by our LVM2 tools (please check it out
at www.sistina.com).
Final (L)GPLed release planned for July.

We will support mirroring directly further down the LVM2 road later this year.

> 
> Not AFAIK.
> 
> Bill
> -- 
> William H. Blunn - <bill+s.9sfuw6uo@tao-group.com> - Developer Support
> Tao
> 62/63 Suttons Business Park, Earley, READING, RG6 1AZ, United Kingdom
> Tel: +44 118 901 2999 - Fax: +44 118 901 2963 - http://tao-group.com/
> 
> The contents of this e-mail and any attachments are confidential and may
> be legally privileged. If you have received this e-mail and you are not
> a named addressee, please inform us as soon as possible on
> +44 118 901 2999 and then delete the e-mail from your system. If you are
> not a named addressee you must not copy, use, disclose, distribute,
> print or rely on this e-mail. Any views expressed in this e-mail or any
> attachments may not necessarily reflect those of Tao's management.
> Although we routinely screen for viruses, addressees should scan this
> e-mail and any attachments for viruses. Tao makes no representation or
> warranty as to the absence of viruses in this e-mail or any attachments.
> Please note that for the protection of our business, we may monitor and
> read e-mails sent to and from our server(s).
> 
> Visit our website at http://tao-group.com/
> 
> _______________________________________________
> 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

-- 

Regards,
Heinz    -- The LVM Guy --

*** Software bugs are stupid.
    Nevertheless it needs not so stupid people to solve them ***

=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-

Heinz Mauelshagen                                 Sistina Software Inc.
Senior Consultant/Developer                       Am Sonnenhang 11
                                                  56242 Marienrachdorf
                                                  Germany
Mauelshagen@Sistina.com                           +49 2626 141200
                                                       FAX 924446
=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-

Re: [linux-lvm] RAID & LVM

[James Hawtin]

On Wed, 26 Jun 2002, Heinz J . Mauelshagen wrote:

> Final (L)GPLed release planned for July.

Forgive me for being very dumb but what does that mean?

Its the Final one that will be released under LGPL????

or

The first (L)GPL release... which will be of the "final" (finished?)
product.

Or

Does it mean its the find (L)GPL release planned for July other will come
later....?

James

Re: [linux-lvm] RAID & LVM

[Heinz J . Mauelshagen]

On Wed, Jun 26, 2002 at 02:23:38PM +0000, James Hawtin wrote:
> 
> 
> On Wed, 26 Jun 2002, Heinz J . Mauelshagen wrote:
> 
> > Final (L)GPLed release planned for July.
> 
> Forgive me for being very dumb but what does that mean?

Well, I could have been more verbose :)

> 
> Its the Final one that will be released under LGPL????
> 
> or
> 
> The first (L)GPL release... which will be of the "final" (finished?)
> product.
> 
> Or
> 
> Does it mean its the find (L)GPL release planned for July other will come
> later....?

LVM2 is our new code base implementing various goodies
(like config file support, huge snapshot performamce improvements)

It is under (L)GPL and we want to replace LVM1 completely with it.

We have had a series of Betas and now will have as few release candidates as possible.

The final LVM2 product is planned to be released in July.

> 
> James
> 
> 
> _______________________________________________
> 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

-- 

Regards,
Heinz    -- The LVM Guy --

*** Software bugs are stupid.
    Nevertheless it needs not so stupid people to solve them ***

=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-

Heinz Mauelshagen                                 Sistina Software Inc.
Senior Consultant/Developer                       Am Sonnenhang 11
                                                  56242 Marienrachdorf
                                                  Germany
Mauelshagen@Sistina.com                           +49 2626 141200
                                                       FAX 924446
=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-

[linux-lvm] raid & LVM

[Jeffrey E. Mast]

I have been playing around with the kernel linux-2.3.99-pre7-8
(0.8final) and attempting to try out
using software raid0 with LVM. The problem I am having is that
apparently /proc/partitions
reports /dev/mda instead of /dev/md0 and pvcreate cannot find /dev/md0.

This may be due to raid not really being incorporated into the kernel
yet or if something else
changed in the kernel. Anyone know why?

Anyway, I made a link from /dev/md0 to /dev/mda and pvcreate works.
However, doing
a vgscan segfaults. The segfault occurs in pv_read_all_pv.c during the
check for MD and
clear out doubles.

Maybe I am being too bold trying this out before the full raid is
incorporated into the kernel, but
I wanted to see what the current status was.

Thanks,

Jeff

Re: [linux-lvm] raid & LVM

[Michael Marxmeier]

"Jeffrey E. Mast" wrote:
> 
> I have been playing around with the kernel linux-2.3.99-pre7-8
> (0.8final) and attempting to try out
> using software raid0 with LVM. The problem I am having is that
> apparently /proc/partitions
> reports /dev/mda instead of /dev/md0 and pvcreate cannot find /dev/md0.

IMHO this might be an inconsistency between devfs and your current
device files (probably non devfs based?). When devfs is compiled in 
the kernel /proc/partitions returns the devfs names.
To save scanning all block device files in /dev, lvm tries to make
use of /proc/partitions in vgscan.

> Anyway, I made a link from /dev/md0 to /dev/mda and pvcreate works.
> However, doing
> a vgscan segfaults. The segfault occurs in pv_read_all_pv.c during the
> check for MD and
> clear out doubles.

Looks like a bug.


Michael

-- 
Michael Marxmeier           Marxmeier Software AG
E-Mail: mike@msede.com      Besenbruchstrasse 9
Phone : +49 202 2431440     42285 Wuppertal, Germany
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