Xen users - Apr 2007 - Re: Managing DomU partitions in XEN+LVM systems?

Hello,

I have a similar problem:

I have a Windows 2003 domU in an LVM partition.
I want to enlarge this partition in order to have more space for windows 2003.

So in your post you say:
> That would seem trivial to do, from within dom0 (while the domU is not
> running of course.)  Just use:
>   - lvextend to enlarge the volume
>   - fdisk (or parted) to enlarge the partition
>  - ntfsresize to enlarge the filesystem
but for me the problem is that fdisk can''t enlarge a partition! It
says you must delete it and then recreate it, but if I do this I lose
all my 2003 system.

How can I enlarge my 2003 partition (and update the MBR for windows to
recognize it)?

ntfsresize tells me:

Current volume size: 10470748672 bytes (10471 MB)
Current device size: 10470749184 bytes (10471 MB)
New volume size    : 10470744576 bytes (10471 MB)
Nothing to do: NTFS volume size is already OK.

So my LVM partition have been enlarged, but ntfsresize don''t see it.
You solved it with fdisk? and how?

Windows 2003 is in one big partition, so it will need to boot after
the resize :)

Thanks for your help!

Jordi.S

On 1/31/07, Derek <xen@sherlockmail.com> wrote:
> Hi all,
>
> This is more an LVM question than a XEN one.   But hopefully not too far
off
> topic for the Xen list...
>
> I am running an HVM domU partitions (WinXP).  I assigned a root drive that
> is an LVM logical volume as seen by the Dom0, in other words:
>
>   disk = [ ''phy:/dev/mapper/main-root_disk_winxp,hda,w'' ,
> ... others ... ]
>
> WinXP''s installer sees the logical volume as a whole disk, and
promptly
> partitions it.  So, it ends up with a partition table and one large NTFS
> filesystem partition.
>
> Now later, I decided to enlarge the logical volume, it''s
associated
> partition, and it''s associated NTFS filesystem.
>
> That would seem trivial to do, from within dom0 (while the domU is not
> running of course.)  Just use:
>   - lvextend to enlarge the volume
>   - fdisk (or parted) to enlarge the partition
>  - ntfsresize to enlarge the filesystem
>
> The first two steps work flawlessly.  The third step is problematic,
because
> ntfsresize wants to be told the device path to the _partition_, not to the
> _whole_disk_.  Well, /dev/mapper/main-root_disk_winxp is
> the whole disk, but there''s no corresponding
> /dev/mapper/main-root_disk_winxp1 for the paritition on
> it.  LVM+UDEV+DM don''t give you one.
>
> I''m not stuck, I have a workaround yet to try:   linux in a domU,
and run
> fdisk+ntfsresize there.  The linux DomU will presumably contain a device
> nodes for the partition, and I can run ntfsresize within it.  But
I''m asking
> this because I''m sure there''s  a more elegant solution,
and someone on this
> list probably knows it.  Surely there''s a way to persuade
LVM+UDEV+DM to
> produce device nodes for each partition within each logical volume?  (I
know
> roughly how to write UDEV rules, but this problem goes beyond that, and I
> definitely don''t understand the device mapper).
>
> Thanks,
> Derek.
>
> _______________________________________________
> Xen-users mailing list
> Xen-users@lists.xensource.com
> http://lists.xensource.com/xen-users
>
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> I have a Windows 2003 domU in an LVM partition.
> I want to enlarge this partition in order to have more space for windows
> 2003.
>
> So in your post you say:
> > That would seem trivial to do, from within dom0 (while the domU is not
> > running of course.)  Just use:
> >   - lvextend to enlarge the volume
> >   - fdisk (or parted) to enlarge the partition
> >  - ntfsresize to enlarge the filesystem
>
> but for me the problem is that fdisk can''t enlarge a partition! It
> says you must delete it and then recreate it, but if I do this I lose
> all my 2003 system.
Well, in principle I guess that ought to work, right?  I mean the data will 
still be there, and once you''ve recreated the partition table it should
be
possible to find the filesystem again.  Mmm?  Maybe try it on a copy for 
safety''s sake?

Doesn''t Windows have any facility for expanding filesystems?  Worst
case, you
could just export another drive to Windows (and, if you want, mount it 
somewhere in the filesystem hierarchy - 2k3 can do that).

Cheers,
Mark
> How can I enlarge my 2003 partition (and update the MBR for windows to
> recognize it)?
>
> ntfsresize tells me:
>
> Current volume size: 10470748672 bytes (10471 MB)
> Current device size: 10470749184 bytes (10471 MB)
> New volume size    : 10470744576 bytes (10471 MB)
> Nothing to do: NTFS volume size is already OK.
>
> So my LVM partition have been enlarged, but ntfsresize don''t see
it.
> You solved it with fdisk? and how?
>
> Windows 2003 is in one big partition, so it will need to boot after
> the resize :)
>
> Thanks for your help!
>
> Jordi.S
>
> On 1/31/07, Derek <xen@sherlockmail.com> wrote:
> > Hi all,
> >
> > This is more an LVM question than a XEN one.   But hopefully not too
far
> > off topic for the Xen list...
> >
> > I am running an HVM domU partitions (WinXP).  I assigned a root drive
> > that is an LVM logical volume as seen by the Dom0, in other words:
> >
> >   disk = [
''phy:/dev/mapper/main-root_disk_winxp,hda,w'' ,
> > ... others ... ]
> >
> > WinXP''s installer sees the logical volume as a whole disk,
and promptly
> > partitions it.  So, it ends up with a partition table and one large
NTFS
> > filesystem partition.
> >
> > Now later, I decided to enlarge the logical volume, it''s
associated
> > partition, and it''s associated NTFS filesystem.
> >
> > That would seem trivial to do, from within dom0 (while the domU is not
> > running of course.)  Just use:
> >   - lvextend to enlarge the volume
> >   - fdisk (or parted) to enlarge the partition
> >  - ntfsresize to enlarge the filesystem
> >
> > The first two steps work flawlessly.  The third step is problematic,
> > because ntfsresize wants to be told the device path to the
_partition_,
> > not to the _whole_disk_.  Well, /dev/mapper/main-root_disk_winxp is
> > the whole disk, but there''s no corresponding
> > /dev/mapper/main-root_disk_winxp1 for the paritition on
> > it.  LVM+UDEV+DM don''t give you one.
> >
> > I''m not stuck, I have a workaround yet to try:   linux in a
domU, and run
> > fdisk+ntfsresize there.  The linux DomU will presumably contain a
device
> > nodes for the partition, and I can run ntfsresize within it.  But
I''m
> > asking this because I''m sure there''s  a more elegant
solution, and
> > someone on this list probably knows it.  Surely there''s a way
to persuade
> > LVM+UDEV+DM to produce device nodes for each partition within each
> > logical volume?  (I know roughly how to write UDEV rules, but this
> > problem goes beyond that, and I definitely don''t understand
the device
> > mapper).
> >
> > Thanks,
> > Derek.
> >
> > _______________________________________________
> > Xen-users mailing list
> > Xen-users@lists.xensource.com
> > http://lists.xensource.com/xen-users
>
> _______________________________________________
> Xen-users mailing list
> Xen-users@lists.xensource.com
> http://lists.xensource.com/xen-users
-- 
Dave: Just a question. What use is a unicyle with no seat?  And no pedals!
Mark: To answer a question with a question: What use is a skateboard?
Dave: Skateboards have wheels.
Mark: My wheel has a wheel!

_______________________________________________
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On 4/19/07, Jordi Segues <jordisd.mailing@gmail.com>
wrote:
> but for me the problem is that fdisk can''t enlarge a partition! It
> says you must delete it and then recreate it, but if I do this I lose
> all my 2003 system.
When I did it, I just used fdisk to delete the partition, and then to
re-create a new one of the larger size.  The new one must start at the
exact same cylinder as the old one did, but can have more cylinders. 
It''s a
little scary because of the messages about data loss, but it worked fine for
me.

To the best of my knowledge, fdisk doesn''t touch any other part of the
disk
other than the partition table, so provided the new partition is larger than
the old, and begins at the same position as the old, everything works fine.

One precaution I took -- and I recommend you do the same.  I first backed up
the entire logical volume, by creating another one of the same size and
using dd to copy the content.  That way, if did anything stupid and broke my
windows filesystem, I''d have been able to recreate it.

Derek.


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Hello,

Thanks for your answers.
It''s exact, when you recreate the table the data is not lost.

There are my commands:

#You extend your LVM partition
lvextend -L +5G /dev/LVM/2003-clone

#Open cfdisk
fdisk /dev/LVM/2003-clone

	#Delete NTFS partition
	#Recreate a bigger NTFS partition
	#Put the boot flag
	#We write changes "W"
	#Quit cfdisk

#We make a ntfsresize, it will extend the old NTFS filesystem to the
new size of the LVM partition
kpartx -a /dev/LVM/2003-clone
ntfsresize /dev/mapper/2003-clonep1
kpartx -d /dev/LVM/2003-clone

#Now windows 2003 boots perfectly, without data loss and with more disk space ;)

On 4/20/07, Derek <xen@sherlockmail.com> wrote:
> On 4/19/07, Jordi Segues <jordisd.mailing@gmail.com> wrote:
> > but for me the problem is that fdisk can''t enlarge a
partition! It
> > says you must delete it and then recreate it, but if I do this I lose
> > all my 2003 system.
>
> When I did it, I just used fdisk to delete the partition, and then to
> re-create a new one of the larger size.  The new one must start at the
> exact same cylinder as the old one did, but can have more cylinders. 
It''s a
> little scary because of the messages about data loss, but it worked fine
for
> me.
>
> To the best of my knowledge, fdisk doesn''t touch any other part of
the disk
> other than the partition table, so provided the new partition is larger
than
> the old, and begins at the same position as the old, everything works fine.
>
> One precaution I took -- and I recommend you do the same.  I first backed
up
> the entire logical volume, by creating another one of the same size and
> using dd to copy the content.  That way, if did anything stupid and broke
my
> windows filesystem, I''d have been able to recreate it.
>
> Derek.
>
> _______________________________________________
> Xen-users mailing list
> Xen-users@lists.xensource.com
> http://lists.xensource.com/xen-users
>
_______________________________________________
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Awesome!  I thought this would work (assuming ntfsresize coped with it).

If you get a chance, it would be really good to have this solution recorded in 
the Xen wiki (http://wiki.xensource.com/)

Cheers,
Mark

On Friday 20 April 2007, Jordi Segues wrote:
> Hello,
>
> Thanks for your answers.
> It''s exact, when you recreate the table the data is not lost.
>
> There are my commands:
>
> #You extend your LVM partition
> lvextend -L +5G /dev/LVM/2003-clone
>
> #Open cfdisk
> fdisk /dev/LVM/2003-clone
>
> 	#Delete NTFS partition
> 	#Recreate a bigger NTFS partition
> 	#Put the boot flag
> 	#We write changes "W"
> 	#Quit cfdisk
>
> #We make a ntfsresize, it will extend the old NTFS filesystem to the
> new size of the LVM partition
> kpartx -a /dev/LVM/2003-clone
> ntfsresize /dev/mapper/2003-clonep1
> kpartx -d /dev/LVM/2003-clone
>
> #Now windows 2003 boots perfectly, without data loss and with more disk
> space ;)
>
> On 4/20/07, Derek <xen@sherlockmail.com> wrote:
> > On 4/19/07, Jordi Segues <jordisd.mailing@gmail.com> wrote:
> > > but for me the problem is that fdisk can''t enlarge a
partition! It
> > > says you must delete it and then recreate it, but if I do this I
lose
> > > all my 2003 system.
> >
> > When I did it, I just used fdisk to delete the partition, and then to
> > re-create a new one of the larger size.  The new one must start at the
> > exact same cylinder as the old one did, but can have more cylinders. 
> > It''s a little scary because of the messages about data loss,
but it
> > worked fine for me.
> >
> > To the best of my knowledge, fdisk doesn''t touch any other
part of the
> > disk other than the partition table, so provided the new partition is
> > larger than the old, and begins at the same position as the old,
> > everything works fine.
> >
> > One precaution I took -- and I recommend you do the same.  I first
backed
> > up the entire logical volume, by creating another one of the same size
> > and using dd to copy the content.  That way, if did anything stupid
and
> > broke my windows filesystem, I''d have been able to recreate
it.
> >
> > Derek.
> >
> > _______________________________________________
> > Xen-users mailing list
> > Xen-users@lists.xensource.com
> > http://lists.xensource.com/xen-users
>
> _______________________________________________
> Xen-users mailing list
> Xen-users@lists.xensource.com
> http://lists.xensource.com/xen-users


-- 
Dave: Just a question. What use is a unicyle with no seat?  And no pedals!
Mark: To answer a question with a question: What use is a skateboard?
Dave: Skateboards have wheels.
Mark: My wheel has a wheel!

_______________________________________________
Xen-users mailing list
Xen-users@lists.xensource.com
http://lists.xensource.com/xen-users

Sorry to intrude into a past thread. But I merely did an lvextend on a windows
image, and then Xen completely refuses to boot itself. It just hangs at the
initial ''booting from harddisk'' stage, and doesn''t
even go to windows. I am using Xen 3.0.4 on RHEL-5. Is this a bug in Xen-3.0?

 Can someone confirm that what''s explained below works properly in
practice? I extended the partition using parted, but even then it
doesn''t go past the initial stage. But again, shouldn''t
windows boot if you merely do an lvextend. I mean, I am not expecting it to
automatically fill the new space--for that ntfsresize, and parted/fdisk are
needed--but should Xen hang at the beginning itself on a mere lvextend?

 what''s the Xen version Jordi used?

 Thanks a lot in advance.


On Friday 20 April 2007, Jordi Segues wrote:
> Hello,
>
> Thanks for your answers.
> It''s exact, when you recreate the table the data is not lost.
>
> There are my commands:
>
> #You extend your LVM partition
> lvextend -L +5G /dev/LVM/2003-clone
>
> #Open cfdisk
> fdisk /dev/LVM/2003-clone
>
> 	#Delete NTFS partition
> 	#Recreate a bigger NTFS partition
> 	#Put the boot flag
> 	#We write changes "W"
> 	#Quit cfdisk
>
> #We make a ntfsresize, it will extend the old NTFS filesystem to the
> new size of the LVM partition
> kpartx -a /dev/LVM/2003-clone
> ntfsresize /dev/mapper/2003-clonep1
> kpartx -d /dev/LVM/2003-clone
>
> #Now windows 2003 boots perfectly, without data loss and with more disk
> space ;)
>
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