[linux-lvm] newbie question

[linux-lvm] newbie question

[JAmes]

Another question I have is can anybody show me a good install plan, a
partition scheme for a machine where everything but the / is lvm'ed. I
haven't seen this discussed anywhere. At the moment I am just testing on a
box with a partition / a swap and a /home .

If I did a standard installation using say 5 partitions / /usr /var/ /home
swap, it would be a pain transferring this to an lvm system. So how do you
lot do it ? WHat sort of installation do you do?

my partitions at the moment

 Device Boot    Start       End    Blocks   Id  System
/dev/hda1   *         1       608   4883728+  83  Linux
/dev/hda2           609       627    152617+  82  Linux swap
/dev/hda3           628       749    979965   83  Linux
/dev/hda4           750      1601   6843690    5  Extended
/dev/hda5           750       871    979933+  8e  Linux LVM
/dev/hda6           872       993    979933+  8e  Linux LVM
/dev/hda7           994      1601   4883728+  8e  Linux LVM

Thanks again.

Re: [linux-lvm] newbie question

[Eric M. Hopper]

[-- Attachment #1: Type: text/plain, Size: 2852 bytes --]

On Fri, Feb 02, 2001 at 04:08:49PM +0100, JAmes wrote:
> 
> Another question I have is can anybody show me a good install plan, a
> partition scheme for a machine where everything but the / is lvm'ed. I
> haven't seen this discussed anywhere. At the moment I am just testing on a
> box with a partition / a swap and a /home .
> 
> If I did a standard installation using say 5 partitions / /usr /var/ /home
> swap, it would be a pain transferring this to an lvm system. So how do you
> lot do it ? WHat sort of installation do you do?
> 
> my partitions at the moment
> 
>  Device Boot    Start       End    Blocks   Id  System
> /dev/hda1   *         1       608   4883728+  83  Linux
> /dev/hda2           609       627    152617+  82  Linux swap
> /dev/hda3           628       749    979965   83  Linux
> /dev/hda4           750      1601   6843690    5  Extended
> /dev/hda5           750       871    979933+  8e  Linux LVM
> /dev/hda6           872       993    979933+  8e  Linux LVM
> /dev/hda7           994      1601   4883728+  8e  Linux LVM
> 
> Thanks again.

	One thing I can say right now is that you _don't_ want more than
one LVM partition on any given physical device.  Actually, it isn't that
bad of a problem unless you try to use LVM to do striping.  Then LVM
gets confused about what is and what isn't a seperate physical device.
Striping across /dev/hda5 and /dev/hda6 in your partitioning scheme
would be a performance disaster.

Here is my partitioning scheme:
   Device Boot    Start       End    Blocks   Id  System
/dev/hda1             1      9859   4968904+   b  Win95 FAT32
/dev/hda2         15457     59303  22098888   8e  Linux LVM
/dev/hda4          9860     15456   2820888   83  Linux  (spare unused)

(That Win95 partition is actually completely unused, and left over from
when I did used to run Win95.)

(The spare unsused partition is used for installing new versions of Linux
from distributions that are neither LVM nor reiserfs aware.)

   Device Boot    Start       End    Blocks   Id  System
/dev/hdc1             1       102     51376+  83  Linux  (/boot)
/dev/hdc2           103     59554  29963808    5  Extended
/dev/hdc5         15708     59554  22098856+  8e  Linux LVM
/dev/hdc6           103     14666   7340224+  83  Linux  (/)
/dev/hdc7         14667     15707    524632+  82  Linux swap

	Notice that there is only one LVM partition per device.  If I
could do it again, I would put swap closer to the beginning of the
device (right after /boot).  Hard-drives typically access data near
their beginning faster.

Have fun (if at all possible),
-- 
The best we can hope for concerning the people at large is that they
be properly armed.  -- Alexander Hamilton
-- Eric Hopper (hopper@omnifarious.mn.org http://www.omnifarious.org/~hopper) --

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Re: [linux-lvm] newbie question

[James]

This is a great help thanks :-)

On Fri, 2 Feb 2001, Eric M. Hopper wrote:

> On Fri, Feb 02, 2001 at 04:08:49PM +0100, JAmes wrote:
> > 
> > Another question I have is can anybody show me a good install plan, a
> > partition scheme for a machine where everything but the / is lvm'ed. I
> > haven't seen this discussed anywhere. At the moment I am just testing on a
> > box with a partition / a swap and a /home .
> > 
> > If I did a standard installation using say 5 partitions / /usr /var/ /home
> > swap, it would be a pain transferring this to an lvm system. So how do you
> > lot do it ? WHat sort of installation do you do?
> > 
> > my partitions at the moment
> > 
> >  Device Boot    Start       End    Blocks   Id  System
> > /dev/hda1   *         1       608   4883728+  83  Linux
> > /dev/hda2           609       627    152617+  82  Linux swap
> > /dev/hda3           628       749    979965   83  Linux
> > /dev/hda4           750      1601   6843690    5  Extended
> > /dev/hda5           750       871    979933+  8e  Linux LVM
> > /dev/hda6           872       993    979933+  8e  Linux LVM
> > /dev/hda7           994      1601   4883728+  8e  Linux LVM
> > 
> > Thanks again.
> 
> 	One thing I can say right now is that you _don't_ want more than
> one LVM partition on any given physical device.  Actually, it isn't that
> bad of a problem unless you try to use LVM to do striping.  Then LVM
> gets confused about what is and what isn't a seperate physical device.
> Striping across /dev/hda5 and /dev/hda6 in your partitioning scheme
> would be a performance disaster.
> 
> Here is my partitioning scheme:
>    Device Boot    Start       End    Blocks   Id  System
> /dev/hda1             1      9859   4968904+   b  Win95 FAT32
> /dev/hda2         15457     59303  22098888   8e  Linux LVM
> /dev/hda4          9860     15456   2820888   83  Linux  (spare unused)
> 
> (That Win95 partition is actually completely unused, and left over from
> when I did used to run Win95.)
> 
> (The spare unsused partition is used for installing new versions of Linux
> from distributions that are neither LVM nor reiserfs aware.)
> 
>    Device Boot    Start       End    Blocks   Id  System
> /dev/hdc1             1       102     51376+  83  Linux  (/boot)
> /dev/hdc2           103     59554  29963808    5  Extended
> /dev/hdc5         15708     59554  22098856+  8e  Linux LVM
> /dev/hdc6           103     14666   7340224+  83  Linux  (/)
> /dev/hdc7         14667     15707    524632+  82  Linux swap
> 
> 	Notice that there is only one LVM partition per device.  If I
> could do it again, I would put swap closer to the beginning of the
> device (right after /boot).  Hard-drives typically access data near
> their beginning faster.
> 
> Have fun (if at all possible),
> -- 
> The best we can hope for concerning the people at large is that they
> be properly armed.  -- Alexander Hamilton
> -- Eric Hopper (hopper@omnifarious.mn.org http://www.omnifarious.org/~hopper) --
> 

Re: [linux-lvm] newbie question

[Andreas Dilger]

James writes:
> If I did a standard installation using say 5 partitions / /usr /var/ /home
> swap, it would be a pain transferring this to an lvm system. So how do you
> lot do it ? WHat sort of installation do you do?

AIX comes with 7 partitions standard:

/ /usr /var /home /tmp swap boot

You can put all of these into Linux LVM, except boot.  That should be
working fairly soon.

> my partitions at the moment
> 
>  Device Boot    Start       End    Blocks   Id  System
> /dev/hda1   *         1       608   4883728+  83  Linux
> /dev/hda2           609       627    152617+  82  Linux swap
> /dev/hda3           628       749    979965   83  Linux
> /dev/hda4           750      1601   6843690    5  Extended
> /dev/hda5           750       871    979933+  8e  Linux LVM
> /dev/hda6           872       993    979933+  8e  Linux LVM
> /dev/hda7           994      1601   4883728+  8e  Linux LVM

I would suggest combining all of the LVM partitions into a single one.
You are wasting space with having multiple LVM partitions on a single
drive, and it doesn't benefit anything.  Each PV can waste up to
(PE size - 1)  bytes, so up to 4MB if you use default PE size.  The only
reason you might want to do this is if you have multiple VGs, but there
is not really a reason to do this with only a single drive.

Cheers, Andreas
-- 
Andreas Dilger  \ "If a man ate a pound of pasta and a pound of antipasto,
                 \  would they cancel out, leaving him still hungry?"
http://www-mddsp.enel.ucalgary.ca/People/adilger/               -- Dogbert

Re: [linux-lvm] newbie question

[James]

Ok, so say I have 1 36gb scsi drive, do I do a basic installation using
say 1gb or less all on the first partition or say with a boot and a /
taking up two partitions? Then when I have everything installed I create a
huge 35gb partition as LVM, create /usr /var /home etc on it and remount
everything there? Then a similar idea when using raid1?

cheers

On Fri, 2 Feb 2001, Andreas Dilger wrote:

> James writes:
> > If I did a standard installation using say 5 partitions / /usr /var/ /home
> > swap, it would be a pain transferring this to an lvm system. So how do you
> > lot do it ? WHat sort of installation do you do?
> 
> AIX comes with 7 partitions standard:
> 
> / /usr /var /home /tmp swap boot
> 
> You can put all of these into Linux LVM, except boot.  That should be
> working fairly soon.
> 
> > my partitions at the moment
> > 
> >  Device Boot    Start       End    Blocks   Id  System
> > /dev/hda1   *         1       608   4883728+  83  Linux
> > /dev/hda2           609       627    152617+  82  Linux swap
> > /dev/hda3           628       749    979965   83  Linux
> > /dev/hda4           750      1601   6843690    5  Extended
> > /dev/hda5           750       871    979933+  8e  Linux LVM
> > /dev/hda6           872       993    979933+  8e  Linux LVM
> > /dev/hda7           994      1601   4883728+  8e  Linux LVM
> 
> I would suggest combining all of the LVM partitions into a single one.
> You are wasting space with having multiple LVM partitions on a single
> drive, and it doesn't benefit anything.  Each PV can waste up to
> (PE size - 1)  bytes, so up to 4MB if you use default PE size.  The only
> reason you might want to do this is if you have multiple VGs, but there
> is not really a reason to do this with only a single drive.
> 
> Cheers, Andreas
> -- 
> Andreas Dilger  \ "If a man ate a pound of pasta and a pound of antipasto,
>                  \  would they cancel out, leaving him still hungry?"
> http://www-mddsp.enel.ucalgary.ca/People/adilger/               -- Dogbert
> _______________________________________________
> linux-lvm mailing list
> linux-lvm@sistina.com
> http://lists.sistina.com/mailman/listinfo/linux-lvm
> 

Re: [linux-lvm] newbie question

[David Gould]

On Fri, Feb 02, 2001 at 09:49:56AM -0600, Eric M. Hopper wrote:
... 
> Here is my partitioning scheme:
>    Device Boot    Start       End    Blocks   Id  System
> /dev/hda1             1      9859   4968904+   b  Win95 FAT32
> /dev/hda2         15457     59303  22098888   8e  Linux LVM
> /dev/hda4          9860     15456   2820888   83  Linux  (spare unused)
> 
> (That Win95 partition is actually completely unused, and left over from
> when I did used to run Win95.)

Well, it would make a fine swap partition ;-)

-dg
 
-- 
David Gould                                                 dg@suse.com
SuSE, Inc.,  580 2cd St. #210,  Oakland, CA 94607          510.628.3380
You left them alone in a room with a penguin?!  Mr Gates, your men are
already dead.

[linux-lvm] syslogd reports: kernel: lvm -- lvm_chr_ioctl: unknown command 4004fe0a

[Theo]

Hello guys.

This is my first time using lvm.

After using pvcreate and vgcreate I rebooted and tried to activate the
volume group.

After the reboot I found the following in the kernel log:
Jul 11 19:40:52 alderaan kernel: LVM version 0.9.1_beta2  by Heinz
Mauelshagen (18/01/2001)
Jul 11 19:40:52 alderaan kernel: lvm -- Driver successfully initialized

Okay the driver is then in the kernel. No problem... later.... in the kernel
log:
Jul 11 19:40:53 alderaan kernel: lvm -- lvm_chr_ioctl: unknown command
4004fe0a

Same same error appears I run "vgchange"

I am a bit confused about this ?

I'm  using slackware 8.0 and I'm using the 2.4.5 kernel that comes with the
bare245.i image file.

Any ideas ?

Re: [linux-lvm] syslogd reports: kernel: lvm -- lvm_chr_ioctl: unknown command 4004fe0a

[Joe Thornber]

we added a new ioctl between beta2 and beta7, it sounds like you are
using newer tools which are expecting the new ioctl to be there.  When
they don't find it they just fall back on the old command so no harm
done, other than a spurious kernel message.

- Joe

On Wed, Jul 11, 2001 at 08:33:14PM +0200, Theo wrote:
> Hello guys.
> 
> This is my first time using lvm.
> 
> After using pvcreate and vgcreate I rebooted and tried to activate the
> volume group.
> 
> After the reboot I found the following in the kernel log:
> Jul 11 19:40:52 alderaan kernel: LVM version 0.9.1_beta2  by Heinz
> Mauelshagen (18/01/2001)
> Jul 11 19:40:52 alderaan kernel: lvm -- Driver successfully initialized
> 
> Okay the driver is then in the kernel. No problem... later.... in the kernel
> log:
> Jul 11 19:40:53 alderaan kernel: lvm -- lvm_chr_ioctl: unknown command
> 4004fe0a
> 
> Same same error appears I run "vgchange"
> 
> I am a bit confused about this ?
> 
> I'm  using slackware 8.0 and I'm using the 2.4.5 kernel that comes with the
> bare245.i image file.
> 
> Any ideas ?
> 
> 
> 
> _______________________________________________
> 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] Newbie question

[Leandro Lucarella]

Hi, I'm new in LVM (I'm so new that I'm not even using it :) and I have a
question:

I want to know if the stiper mode, the performance gain is somparable to Software
RAID 0.
Another question is the boot stuff, what is better? compile LVM as a module
and use inird or compile the kernel with built-in LVM support?
Thanks for your help...

--
LUCA - Leandro Lucarella
------------------------
luca@lucarella.com.ar
http://www.luca.2y.net
LICQ UIN: 2847576
------------------------
Usando Debian GNU/Linux

RE: [linux-lvm] syslogd reports: kernel: lvm -- lvm_chr_ioctl: unknown command 4004fe0a

[Johann]

I noted the version difference and patched the kernel and utils to the
lastest version.

Thanx for your help.

-----Original Message-----
From: linux-lvm-admin@sistina.com [mailto:linux-lvm-admin@sistina.com]On
Behalf Of Joe Thornber
Sent: 12 July 2001 10:47
To: linux-lvm@sistina.com
Subject: Re: [linux-lvm] syslogd reports: kernel: lvm -- lvm_chr_ioctl:
unknown command 4004fe0a


we added a new ioctl between beta2 and beta7, it sounds like you are
using newer tools which are expecting the new ioctl to be there.  When
they don't find it they just fall back on the old command so no harm
done, other than a spurious kernel message.

- Joe

On Wed, Jul 11, 2001 at 08:33:14PM +0200, Theo wrote:
> Hello guys.
>
> This is my first time using lvm.
>
> After using pvcreate and vgcreate I rebooted and tried to activate the
> volume group.
>
> After the reboot I found the following in the kernel log:
> Jul 11 19:40:52 alderaan kernel: LVM version 0.9.1_beta2  by Heinz
> Mauelshagen (18/01/2001)
> Jul 11 19:40:52 alderaan kernel: lvm -- Driver successfully initialized
>
> Okay the driver is then in the kernel. No problem... later.... in the
kernel
> log:
> Jul 11 19:40:53 alderaan kernel: lvm -- lvm_chr_ioctl: unknown command
> 4004fe0a
>
> Same same error appears I run "vgchange"
>
> I am a bit confused about this ?
>
> I'm  using slackware 8.0 and I'm using the 2.4.5 kernel that comes with
the
> bare245.i image file.
>
> Any ideas ?
>
>
>
> _______________________________________________
> 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

Re: [linux-lvm] Newbie question

[Heinz J. Mauelshagen]

On Thu, Jul 12, 2001 at 11:53:58AM -0300, Leandro Lucarella wrote:
> Hi, I'm new in LVM (I'm so new that I'm not even using it :) and I have a
> question:
> 
> I want to know if the stiper mode, the performance gain is somparable to Software
> RAID 0.

In theory they should be pretty similar :-)

But people reported differences which are probably caused by their particular
hardware setup.

In order to answer the question for your particular configuration, you should
test both ;-)

> Another question is the boot stuff, what is better? compile LVM as a module
> and use inird or compile the kernel with built-in LVM support?

It doesn't make a difference if you go for the module or the build in driver,
you need to have an initrd today anyway to activate your VGs at boot time.

We are working on boot time recognition of VGs in the driver which will vanish
the initrd. That will be in a post 1.0 version of the Linux LVM.

Regards,
Heinz    -- The LVM Guy --


> Thanks for your help...
> 
> --
> LUCA - Leandro Lucarella
> ------------------------
> luca@lucarella.com.ar
> http://www.luca.2y.net
> LICQ UIN: 2847576
> ------------------------
> Usando Debian GNU/Linux
> 
> _______________________________________________
> 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

*** 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[2]: [linux-lvm] Newbie question

[Leandro Lucarella]

El Fri, 13 Jul 2001 13:12:00 +0200 Heinz J. Mauelshagen <Mauelshagen@sistina.com> escribió:

HJM> On Thu, Jul 12, 2001 at 11:53:58AM -0300, Leandro Lucarella wrote:
HJM> > Hi, I'm new in LVM (I'm so new that I'm not even using it :) and I have a
HJM> > question:
HJM> > 
HJM> > I want to know if the stiper mode, the performance gain is somparable to Software
HJM> > RAID 0.
HJM> 
HJM> In theory they should be pretty similar :-)
HJM> 
HJM> But people reported differences which are probably caused by their particular
HJM> hardware setup.
HJM> 
HJM> In order to answer the question for your particular configuration, you should
HJM> test both ;-)

Fair enought for me! LVM has some good advanges so if the performance is
comparable, I'm with LVM! ;)
Now I have a question. I read the HOWTO migrate the old root partition to a
LV, and the method is to make a LV on another HD (or the same if it's
room), copy the root FS to this LV, delete the old partition and add it to
the new LV. My question is. It's possible to make a VG without striping
('cause I have just 1 HD in the begining) and then, when I add the old
partition to the VG, make this VG to do striping????
(I'm really sory about my primitive english... ;)

HJM> > Another question is the boot stuff, what is better? compile LVM as a module
HJM> > and use inird or compile the kernel with built-in LVM support?
HJM> 
HJM> It doesn't make a difference if you go for the module or the build in driver,
HJM> you need to have an initrd today anyway to activate your VGs at boot time.
HJM> 
HJM> We are working on boot time recognition of VGs in the driver which will vanish
HJM> the initrd. That will be in a post 1.0 version of the Linux LVM.

OK, initrd is allways needed until 1.0...
And how close we are to this release??? ;)

--
LUCA - Leandro Lucarella
------------------------
luca@lucarella.com.ar
http://www.luca.2y.net
LICQ UIN: 2847576
------------------------
Usando Debian GNU/Linux

Re: [linux-lvm] Newbie question

[Vincent Bernat]

Le Fri Jul 13, 2001 at 12:33 -0300, 
Leandro Lucarella <luca@lucarella.com.ar> disait :

> Now I have a question. I read the HOWTO migrate the old root partition to a
> LV, and the method is to make a LV on another HD (or the same if it's
> room), copy the root FS to this LV, delete the old partition and add it to
> the new LV. My question is. It's possible to make a VG without striping
> ('cause I have just 1 HD in the begining) and then, when I add the old
> partition to the VG, make this VG to do striping????

The FAQ seems to say it is not possible. You cannot add a PV to a
stripping LV. It may change in the future.

Re: [linux-lvm] Newbie question

[Luca Berra]

On Fri, Jul 13, 2001 at 01:12:00PM +0200, Heinz J. Mauelshagen wrote:
> > Another question is the boot stuff, what is better? compile LVM as a module
> > and use inird or compile the kernel with built-in LVM support?
> 
> It doesn't make a difference if you go for the module or the build in driver,
> you need to have an initrd today anyway to activate your VGs at boot time.
> 
> We are working on boot time recognition of VGs in the driver which will vanish
> the initrd. That will be in a post 1.0 version of the Linux LVM.

is this still worthwile since i read Linus in thinking of a new way
to handle initrd (appending a tar file to a kernel image and populating
a ramfs with it) and moving many _init code that now bloats kernel
to userspace.

Regards,
L.

-- 
Luca Berra -- bluca@comedia.it
        Communication Media & Services S.r.l.
 /"\
 \ /     ASCII RIBBON CAMPAIGN
  X        AGAINST HTML MAIL
 / \

Re: [linux-lvm] Newbie question

[Heinz J. Mauelshagen]

On Fri, Jul 13, 2001 at 06:41:53PM +0200, Vincent Bernat wrote:
> Le Fri Jul 13, 2001 at 12:33 -0300, 
> Leandro Lucarella <luca@lucarella.com.ar> disait :
> 
> > Now I have a question. I read the HOWTO migrate the old root partition to a
> > LV, and the method is to make a LV on another HD (or the same if it's
> > room), copy the root FS to this LV, delete the old partition and add it to
> > the new LV. My question is. It's possible to make a VG without striping
> > ('cause I have just 1 HD in the begining) and then, when I add the old
> > partition to the VG, make this VG to do striping????
> 
> The FAQ seems to say it is not possible. You cannot add a PV to a
> stripping LV. It may change in the future.

True.

> _______________________________________________
> 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] Newbie question

[Heinz J. Mauelshagen]

On Fri, Jul 13, 2001 at 12:33:31PM -0300, Leandro Lucarella wrote:
> El Fri, 13 Jul 2001 13:12:00 +0200 Heinz J. Mauelshagen <Mauelshagen@sistina.com> escribi�:
> 
> HJM> On Thu, Jul 12, 2001 at 11:53:58AM -0300, Leandro Lucarella wrote:
> HJM> > Hi, I'm new in LVM (I'm so new that I'm not even using it :) and I have a
> HJM> > question:
> HJM> > 
> HJM> > I want to know if the stiper mode, the performance gain is somparable to Software
> HJM> > RAID 0.
> HJM> 
> HJM> In theory they should be pretty similar :-)
> HJM> 
> HJM> But people reported differences which are probably caused by their particular
> HJM> hardware setup.
> HJM> 
> HJM> In order to answer the question for your particular configuration, you should
> HJM> test both ;-)
> 
> Fair enought for me! LVM has some good advanges so if the performance is
> comparable, I'm with LVM! ;)
> Now I have a question. I read the HOWTO migrate the old root partition to a
> LV, and the method is to make a LV on another HD (or the same if it's
> room), copy the root FS to this LV, delete the old partition and add it to
> the new LV. My question is. It's possible to make a VG without striping
> ('cause I have just 1 HD in the begining) and then, when I add the old
> partition to the VG, make this VG to do striping????

No, as stated in another answer.

> (I'm really sory about my primitive english... ;)

You shouldn't be. My own is primitive too ;-)

> 
> HJM> > Another question is the boot stuff, what is better? compile LVM as a module
> HJM> > and use inird or compile the kernel with built-in LVM support?
> HJM> 
> HJM> It doesn't make a difference if you go for the module or the build in driver,
> HJM> you need to have an initrd today anyway to activate your VGs at boot time.
> HJM> 
> HJM> We are working on boot time recognition of VGs in the driver which will vanish
> HJM> the initrd. That will be in a post 1.0 version of the Linux LVM.
> 
> OK, initrd is allways needed until 1.0...

No, it will be needed at least including 1.0.
We'll enhance that later.

> And how close we are to this release??? ;)
> 
> --
> LUCA - Leandro Lucarella
> ------------------------
> luca@lucarella.com.ar
> http://www.luca.2y.net
> LICQ UIN: 2847576
> ------------------------
> Usando Debian GNU/Linux
> 
> _______________________________________________
> 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] Newbie question

[Heinz J. Mauelshagen]

On Fri, Jul 13, 2001 at 08:01:13PM +0200, Luca Berra wrote:
> On Fri, Jul 13, 2001 at 01:12:00PM +0200, Heinz J. Mauelshagen wrote:
> > > Another question is the boot stuff, what is better? compile LVM as a module
> > > and use inird or compile the kernel with built-in LVM support?
> > 
> > It doesn't make a difference if you go for the module or the build in driver,
> > you need to have an initrd today anyway to activate your VGs at boot time.
> > 
> > We are working on boot time recognition of VGs in the driver which will vanish
> > the initrd. That will be in a post 1.0 version of the Linux LVM.
> 
> is this still worthwile since i read Linus in thinking of a new way
> to handle initrd (appending a tar file to a kernel image and populating
> a ramfs with it) and moving many _init code that now bloats kernel
> to userspace.

Yes, we do move the functions to read metadata into the LVM kernel code
because we need them in the cluster case anyway.

> 
> Regards,
> L.
> 
> -- 
> Luca Berra -- bluca@comedia.it
>         Communication Media & Services S.r.l.
>  /"\
>  \ /     ASCII RIBBON CAMPAIGN
>   X        AGAINST HTML MAIL
>  / \
> _______________________________________________
> 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] Newbie question

[Steven Lembark]

>> Now I have a question. I read the HOWTO migrate the old root partition to a
>> LV

Think really, really hard before trying this.  Linux on an X86 doesn't have
an LVM aware bios and you cannot boot w/o LVM (e.g., HP's "-lm").  This
means that if you have any error at all in LVM you cannot boot.

A safer approach -- especially if you havn't used LVM before -- is to use
the first 2-3 partitions for /, swap and /var.  This allows you to boot even if
LVM is down and fix most LVM problems.  None of these partitions needs
to be large (e.g., 80, 64 & 320MB) and the remaining partition can be used
as a PV.

sl

Re: [linux-lvm] Newbie question

[Luca Berra]

On Mon, Jul 16, 2001 at 10:08:02AM -0500, Steven Lembark wrote:
> 
> >> Now I have a question. I read the HOWTO migrate the old root partition to a
> >> LV
> 
> Think really, really hard before trying this.  Linux on an X86 doesn't have
> an LVM aware bios and you cannot boot w/o LVM (e.g., HP's "-lm").  This
> means that if you have any error at all in LVM you cannot boot.

and HP9000 haven't either!
-lm works because the vg layout is saved in a file in /stand
they have LVM activation in the kernel tough (sorta, they still need a contiguous root, placed
on the same PV as the kernel is)

> A safer approach -- especially if you havn't used LVM before -- is to use
> the first 2-3 partitions for /, swap and /var.  This allows you to boot even if
maybe / if linux had a sane use for /sbin, but swap and var are unneeded.

(btw i have lvm root and i am happy)

L.

-- 
Luca Berra -- bluca@comedia.it
        Communication Media & Services S.r.l.
 /"\
 \ /     ASCII RIBBON CAMPAIGN
  X        AGAINST HTML MAIL
 / \

Re: [linux-lvm] Newbie question

[josv]

Hi all,

Just for the record, HP-UX's vg layout is not in /stand. Information about
essential logical volumes (boot (/stand), root (/), primary swap and dump) 
is stored in a LIF file (LABEL) in the boot area's of the disk (use the lifls 
command to display the structure of the boot area). The lvlnboot command is used
to query and change the LABEL file. The mapping between VG and PV's is stored
in the /etc/lvmtab file. This file is used by the vgchange command to activate
volume groups. At boot time, /etc/lvmrc is run from the inittab, and it
executes a 'vgchange -a y' for all volume groups.

The "-lm" boot option in HP-UX disables the lv driver (major 64), so only the
/stand, /, pri swap and dump "volumes" are available. Not as logical volumes,
but directly from the disk because these volumes must be contiguous. This
option is necessary in HP-UX since it basically only supports LVM disk setups
(whole disk layout is also supported, but almost never used...). If Linux
would ever get to the point that LVM (or its successor) is *the* choice for
partitioning all disks (even the boot disk), we would need such an option as
well because otherwise there would be no path to recovery in case of LVM
data corruption.

With Veritas Volume Manager you have the option to encapsulate the boot disk.
The encapsulation process turns the boot disk in a PV (terminology: VM disk)
with a bunch of (logical) volumes laid out at exactly the same disk blocks as
the root, swap, usr and other partitions. I have very bad experiences with
encapsulated boot disks in Solaris, and never use them if I can help it.
For that reason I do not really favour converting my entire Linux boot disk
to LVM. But that's just a personal opinion......

++Jos
"Who could not resist commenting on this, sorry..."

And thus it came to pass that Luca Berra wrote:
(on Tue, Jul 17, 2001 at 01:36:10AM +0200 to be exact)

> On Mon, Jul 16, 2001 at 10:08:02AM -0500, Steven Lembark wrote:
> > 
> > >> Now I have a question. I read the HOWTO migrate the old root partition to a
> > >> LV
> > 
> > Think really, really hard before trying this.  Linux on an X86 doesn't have
> > an LVM aware bios and you cannot boot w/o LVM (e.g., HP's "-lm").  This
> > means that if you have any error at all in LVM you cannot boot.
> 
> and HP9000 haven't either!
> -lm works because the vg layout is saved in a file in /stand
> they have LVM activation in the kernel tough (sorta, they still need a contiguous root, placed
> on the same PV as the kernel is)
> 
> > A safer approach -- especially if you havn't used LVM before -- is to use
> > the first 2-3 partitions for /, swap and /var.  This allows you to boot even if
> maybe / if linux had a sane use for /sbin, but swap and var are unneeded.
> 
> (btw i have lvm root and i am happy)
> 
> L.
> 
> -- 
> Luca Berra -- bluca@comedia.it
>         Communication Media & Services S.r.l.
>  /"\
>  \ /     ASCII RIBBON CAMPAIGN
>   X        AGAINST HTML MAIL
>  / \
> _______________________________________________
> 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

-- 
With all the things you are losing,
You might as well resign yourself,
And try and make a change...

Re: [linux-lvm] Newbie question

[Heinz J. Mauelshagen]

On Tue, Jul 17, 2001 at 10:31:59AM +0200, josv@osp.nl wrote:
> Hi all,
> 
> Just for the record, HP-UX's vg layout is not in /stand. Information about
> essential logical volumes (boot (/stand), root (/), primary swap and dump) 
> is stored in a LIF file (LABEL) in the boot area's of the disk (use the lifls 
> command to display the structure of the boot area). The lvlnboot command is used
> to query and change the LABEL file. The mapping between VG and PV's is stored
> in the /etc/lvmtab file. This file is used by the vgchange command to activate
> volume groups. At boot time, /etc/lvmrc is run from the inittab, and it
> executes a 'vgchange -a y' for all volume groups.
> 
> The "-lm" boot option in HP-UX disables the lv driver (major 64), so only the
> /stand, /, pri swap and dump "volumes" are available. Not as logical volumes,
> but directly from the disk because these volumes must be contiguous.

IOW: they encapsulate root, dump and primary swap (pretty often dump
     and swap are the same) as LVs, which therfore never can take full
     advantage of LV features like extension, data relocation etc.

> This
> option is necessary in HP-UX since it basically only supports LVM disk setups
> (whole disk layout is also supported, but almost never used...). If Linux
> would ever get to the point that LVM (or its successor) is *the* choice for
> partitioning all disks (even the boot disk), we would need such an option as
> well because otherwise there would be no path to recovery in case of LVM
> data corruption.

That's a reason why future post 1.0 Linux LVM versions will have enhanced
redundancy in the metadata *and* checksums on every structure there to have
better and faster consistency checks on them.
Another one is that we nead enhanced metadata reliability anyway to activate
essential LVs (like the one containing the root filesystem and such).

> 
> With Veritas Volume Manager you have the option to encapsulate the boot disk.
> The encapsulation process turns the boot disk in a PV (terminology: VM disk)
> with a bunch of (logical) volumes laid out at exactly the same disk blocks as
> the root, swap, usr and other partitions. I have very bad experiences with
> encapsulated boot disks in Solaris, and never use them if I can help it.
> For that reason I do not really favour converting my entire Linux boot disk
> to LVM. But that's just a personal opinion......
> 
> ++Jos
> "Who could not resist commenting on this, sorry..."

That prevented me from doing it ;-))
Oops, did it anyway.

Heinz

> 
> And thus it came to pass that Luca Berra wrote:
> (on Tue, Jul 17, 2001 at 01:36:10AM +0200 to be exact)
> 
> > On Mon, Jul 16, 2001 at 10:08:02AM -0500, Steven Lembark wrote:
> > > 
> > > >> Now I have a question. I read the HOWTO migrate the old root partition to a
> > > >> LV
> > > 
> > > Think really, really hard before trying this.  Linux on an X86 doesn't have
> > > an LVM aware bios and you cannot boot w/o LVM (e.g., HP's "-lm").  This
> > > means that if you have any error at all in LVM you cannot boot.
> > 
> > and HP9000 haven't either!
> > -lm works because the vg layout is saved in a file in /stand
> > they have LVM activation in the kernel tough (sorta, they still need a contiguous root, placed
> > on the same PV as the kernel is)
> > 
> > > A safer approach -- especially if you havn't used LVM before -- is to use
> > > the first 2-3 partitions for /, swap and /var.  This allows you to boot even if
> > maybe / if linux had a sane use for /sbin, but swap and var are unneeded.
> > 
> > (btw i have lvm root and i am happy)
> > 
> > L.
> > 
> > -- 
> > Luca Berra -- bluca@comedia.it
> >         Communication Media & Services S.r.l.
> >  /"\
> >  \ /     ASCII RIBBON CAMPAIGN
> >   X        AGAINST HTML MAIL
> >  / \
> > _______________________________________________
> > 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
> 
> -- 
> With all the things you are losing,
> You might as well resign yourself,
> And try and make a change...
> _______________________________________________
> 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] Newbie question

[Luca Berra]

sorry if i am getting way offtopic here but reply is a must

On Tue, Jul 17, 2001 at 10:31:59AM +0200, josv@osp.nl wrote:
> Hi all,
> 
> Just for the record, HP-UX's vg layout is not in /stand. Information about
> essential logical volumes (boot (/stand), root (/), primary swap and dump) 
> is stored in a LIF file (LABEL) in the boot area's of the disk (use the lifls 
> command to display the structure of the boot area). The lvlnboot command is used
i was referring to:
(from the lvlnboot manpage)
 FILES
      /stand/rootconf          Contains the location of the root volume.
                               Used during maintenance-mode boots (see
                               hpux(1M)) to locate the root volume for
                               volume groups with separate boot and root
                               volumes.

ok, i was not exactly correct but if you follow me you will maybe
pardon me.
Steven stated that hpux -lm worked because HP9000 were able to
understand LVM in firmware.
i stated that hpux -lm works because lvm info is stored in a file in
stand.

The real truth:
/stand/rootconf does not contain LVM info
it just contains info about the location on disk of the root lv
meening starting offset and lenght (it is used only on split
boot/root configurations when booting in LVM mainteinance mode)

on my workstation
# od -x /stand/rootconf
0000000 dead beef 000d 5b60 0004 0000
       | magic   | offset  | size

/stand/rootconf is created/updated using lvlnboot -c


lvlnboot updates both the LABEL file and the BRDA on the PV
the kernel during normal boot reads the BRDA, not the LABEL file
the LABEL file is used by the hpux utility, it is also used
by offline diagnostics.

> to query and change the LABEL file. The mapping between VG and PV's is stored
> in the /etc/lvmtab file. This file is used by the vgchange command to activate
> volume groups. At boot time, /etc/lvmrc is run from the inittab, and it
> executes a 'vgchange -a y' for all volume groups.
this is not strictly correct (lvmrc is a script anc can/must be customized
not to activate all VGs in a clustered environment)

> The "-lm" boot option in HP-UX disables the lv driver (major 64), so only the
> /stand, /, pri swap and dump "volumes" are available. Not as logical volumes,
> but directly from the disk because these volumes must be contiguous. This
this is just plain wrong
only root is available to the system in lvm maint mode (via /stand/rootconf)
/stand and pri swap are not, let alone dump.
/stand must be contiguous at the beginning of the boot disk so the
hpux utility can read a kernel off it
/ must also be contiguous on the boot disk so the kernel can map it
swap and dump can be on any disk (the latter only if IODC is able to
map it) and must be both contiguous. (yes primary swap does not need
to be on lvol2 and on the first disk, altough this is the default)

> option is necessary in HP-UX since it basically only supports LVM disk setups
> (whole disk layout is also supported, but almost never used...). If Linux
AFAIRC whole disk works only on disks < 1GB or so

> would ever get to the point that LVM (or its successor) is *the* choice for
> partitioning all disks (even the boot disk), we would need such an option as
> well because otherwise there would be no path to recovery in case of LVM
> data corruption.

honestly i believe having a resizable root volume is better than being able to
mount root without using lvm. since i can stick enough tools to recover lvm in
an initrd or on a emergency cd-rom.

....
> ++Jos
> "Who could not resist commenting on this, sorry..."

me neither, sorry again....

L.
-- 
Luca Berra -- bluca@comedia.it
        Communication Media & Services S.r.l.
 /"\
 \ /     ASCII RIBBON CAMPAIGN
  X        AGAINST HTML MAIL
 / \

Re: [linux-lvm] Newbie question

[Heinz J. Mauelshagen]

On Tue, Jul 17, 2001 at 09:58:11PM +0200, Luca Berra wrote:
> sorry if i am getting way offtopic here but reply is a must
> 
> On Tue, Jul 17, 2001 at 10:31:59AM +0200, josv@osp.nl wrote:
> > Hi all,
> > 
> > Just for the record, HP-UX's vg layout is not in /stand. Information about
> > essential logical volumes (boot (/stand), root (/), primary swap and dump) 
> > is stored in a LIF file (LABEL) in the boot area's of the disk (use the lifls 
> > command to display the structure of the boot area). The lvlnboot command is used
> i was referring to:
> (from the lvlnboot manpage)
>  FILES
>       /stand/rootconf          Contains the location of the root volume.
>                                Used during maintenance-mode boots (see
>                                hpux(1M)) to locate the root volume for
>                                volume groups with separate boot and root
>                                volumes.
> 
> ok, i was not exactly correct but if you follow me you will maybe
> pardon me.

:)

> Steven stated that hpux -lm worked because HP9000 were able to
> understand LVM in firmware.
> i stated that hpux -lm works because lvm info is stored in a file in
> stand.

Luca is right: PDC (Processor Dependant Code; that's their kind of BIOS) doesn't
know anything about LVM. It understands LIF (Logical Interchange Format; kind
of a very simple filesystem)

> 
> The real truth:
> /stand/rootconf does not contain LVM info
> it just contains info about the location on disk of the root lv
> meening starting offset and lenght (it is used only on split
> boot/root configurations when booting in LVM mainteinance mode)
> 
> on my workstation
> # od -x /stand/rootconf
> 0000000 dead beef 000d 5b60 0004 0000
>        | magic   | offset  | size
> 
> /stand/rootconf is created/updated using lvlnboot -c
> 
> 
> lvlnboot updates both the LABEL file and the BRDA on the PV
> the kernel during normal boot reads the BRDA, not the LABEL file
> the LABEL file is used by the hpux utility, it is also used
> by offline diagnostics.

Sorry for sounding picky:

rootconf contains that information *but* the info is used to
switch to the real *root* filsystem which is necessary in HP-UX in order
to have root journaled (supported since HP-UX 10.20 IIRC).

The offset and length above is for sure the one of the root LV, because the
root LV needs to be contiguous with its LEs in sequential ascending order.
*But* as stated below, the LVM driver is deactivated in LVM maintenance
mode. Therefore the kernel mainly reads the offset info from /stand/rootconf
(BTW: stand is mounted as root at that point in time) in order to switch
to the 'real' root filesystem.

BTW: as briefly said above, seperate stand/root filesystem are
     necessary in HP-UX in order to have root journaled.
     If you need to recreate such a stand/root configuration after a crash
     and you don't do that with *exactly the same* VG parameters for the root
     VG, this leads to a different root LV offset. An unconditional restore to
     /stand will cause an unbootable system, because the restored offset in
     /stand/rootconf is incorrect then :-(
     In this case only a nice echo trick to recreate /stand/rootconf
     (knowing HP VGDA size params) can bring your system back to life again ;-)

> 
> > to query and change the LABEL file. The mapping between VG and PV's is stored
> > in the /etc/lvmtab file. This file is used by the vgchange command to activate
> > volume groups. At boot time, /etc/lvmrc is run from the inittab, and it
> > executes a 'vgchange -a y' for all volume groups.
> this is not strictly correct (lvmrc is a script anc can/must be customized
> not to activate all VGs in a clustered environment)
> 
> > The "-lm" boot option in HP-UX disables the lv driver (major 64), so only the
> > /stand, /, pri swap and dump "volumes" are available. Not as logical volumes,
> > but directly from the disk because these volumes must be contiguous. This
> this is just plain wrong
> only root is available to the system in lvm maint mode (via /stand/rootconf)
> /stand and pri swap are not, let alone dump.
> /stand must be contiguous at the beginning of the boot disk so the
> hpux utility can read a kernel off it
> / must also be contiguous on the boot disk so the kernel can map it
> swap and dump can be on any disk (the latter only if IODC is able to
> map it) and must be both contiguous. (yes primary swap does not need
> to be on lvol2 and on the first disk, altough this is the default)
> 
> > option is necessary in HP-UX since it basically only supports LVM disk setups
> > (whole disk layout is also supported, but almost never used...). If Linux
> AFAIRC whole disk works only on disks < 1GB or so
> 
> > would ever get to the point that LVM (or its successor) is *the* choice for
> > partitioning all disks (even the boot disk), we would need such an option as
> > well because otherwise there would be no path to recovery in case of LVM
> > data corruption.
> 
> honestly i believe having a resizable root volume is better than being able to
> mount root without using lvm. since i can stick enough tools to recover lvm in
> an initrd or on a emergency cd-rom.

Agreed.

> 
> ....
> > ++Jos
> > "Who could not resist commenting on this, sorry..."
> 
> me neither, sorry again....

:)

> 
> L.
> -- 
> Luca Berra -- bluca@comedia.it
>         Communication Media & Services S.r.l.
>  /"\
>  \ /     ASCII RIBBON CAMPAIGN
>   X        AGAINST HTML MAIL
>  / \
> 
> _______________________________________________
> 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] newbie question

[shri krishnan]

Hi,

I was wondering if linux-lvm ever requires unpartitioned space at the end
of a disk for storing volume metadata, similar to Windows dynamic disk.
I've skimmed the source code a bit, and from what I can tell, it seems
that metadata is always stored at the start of each disk partition, but
I wasn't sure if this is always the case. 

Thanks, 

--shri


__________________________________________________
Do You Yahoo!?
Yahoo! - Official partner of 2002 FIFA World Cup
http://fifaworldcup.yahoo.com

Re: [linux-lvm] newbie question

[Heinz J . Mauelshagen]

On Tue, Jun 25, 2002 at 12:28:48PM -0700, shri krishnan wrote:
> Hi,
> 
> I was wondering if linux-lvm ever requires unpartitioned space at the end
> of a disk for storing volume metadata, similar to Windows dynamic disk.
> I've skimmed the source code a bit, and from what I can tell, it seems
> that metadata is always stored at the start of each disk partition, but
> I wasn't sure if this is always the case. 

The ondisk metadata in LVM1 is *always* stored at the very start
of each block device used as a physical volume. Depending on the extent size
(see "vgchange -s") and the size of the physical volume the metadata uses
aproximatly between some 100KB and a couple of MB. You can check this
with "pvdata -PP /dev/PVDev" which will display the various parts of the
LVM1 metadata or so called VGDA (Volume Group Descriptor Area) with their
offsets and sizes.

LVM2 enhances this by supporting multiple ondisk formats and therefore
this could eventually change things in the future ie. putting metadata
redundantly at the beginning and the end of a physical volume.

> 
> Thanks, 
> 
> --shri
> 
> 
> __________________________________________________
> Do You Yahoo!?
> Yahoo! - Official partner of 2002 FIFA World Cup
> http://fifaworldcup.yahoo.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 ***

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