CentOS - Feb 2010 - Resizing a PV that belongs within a Volume Group?

Hi,

I was wondering if there was a way to extend (ie: grow) a PV that is part of
a Volume Group?  I currently have a partition on my HD that is being used as
a PV for my Volume Group, but would like to make it larger.  I have the
space on my drive to extend my partition, but using standard tools (ex:
gparted, Partition Magic, etc) would likely end up corrupting the data on in
the Logical Volumes that are housed within the VG.

I realize that I could just create a new partition on my HD and just add it
to my Volume Group and extend my Volume Group, however, given that it would
be two contiguous partitions on the HD, I was just wondering if there was a
way of resizing the original partition within the VG without causing any
problems.

I tried looking at tools like pvresize but I can't seem to understand the 
right arguments to use it as whatever I try never seems to resize the 
original partition itself.  I also looked at system-config-lvm GUI tool, but 
that doesn't seem to allow me to make the PV any larger.

Does anyone have any suggestions?

Thanks!

Eric

On 19/02/10 10:11, Eric B. wrote:
> Hi,
>
> I was wondering if there was a way to extend (ie: grow) a PV that is part
of
> a Volume Group?  I currently have a partition on my HD that is being used
as
> a PV for my Volume Group, but would like to make it larger.  I have the
> space on my drive to extend my partition, but using standard tools (ex:
> gparted, Partition Magic, etc) would likely end up corrupting the data on
in
> the Logical Volumes that are housed within the VG.
>
> I realize that I could just create a new partition on my HD and just add it
> to my Volume Group and extend my Volume Group, however, given that it would
> be two contiguous partitions on the HD, I was just wondering if there was a
> way of resizing the original partition within the VG without causing any
> problems.
>
> I tried looking at tools like pvresize but I can't seem to understand
the
> right arguments to use it as whatever I try never seems to resize the
> original partition itself.  I also looked at system-config-lvm GUI tool,
but
> that doesn't seem to allow me to make the PV any larger.
>
> Does anyone have any suggestions?
>
> Thanks!
>
> Eric
>
>
>
>
> _______________________________________________
> CentOS mailing list
> CentOS at centos.org
> http://lists.centos.org/mailman/listinfo/centos
>
>    
Hi I remember having done this once recently on a test system.  And I 
strongly suggest you don't attempt unless you have a good backup.  You 
use the standard tools to resize the partition and then pvresize to see 
the new size of the PV.  Once you can see that the new size of the PV is 
recognised by the VG you can allocate the space.

> Hi,
>
> I was wondering if there was a way to extend (ie: grow) a PV that is part
> of
> a Volume Group?  I currently have a partition on my HD that is being used
> as
> a PV for my Volume Group, but would like to make it larger.  I have the
> space on my drive to extend my partition, but using standard tools (ex:
> gparted, Partition Magic, etc) would likely end up corrupting the data on
> in
> the Logical Volumes that are housed within the VG.
[ ... ]
> I tried looking at tools like pvresize but I can't seem to understand
the
> right arguments to use it as whatever I try never seems to resize the
> original partition itself.  I also looked at system-config-lvm GUI tool,
> but
> that doesn't seem to allow me to make the PV any larger.
>
> Does anyone have any suggestions?
>
> Thanks!
>
> Eric
Given the partition which is a physical volume can be enlarged because
there is free space directly after the end of the current partition, you
then can do following very easily:

1) fdisk /dev/<device>
1a) delete the partition to enlarge
1b) re-create the partition from the same starting point to the new size
1c) save the changes

2) partprobe /dev/<device>
   to let the kernel know about the change

3) pvresize /dev/<deviceNUM>
   increases the PV to maximum partition size (just as the manpage says)

4) pvdisplay /dev/<deviceNUM>
   should show you now free physical extends (vgdisplay as well)

5) lvresize -L +100%FREE /dev/mapper/<LVM-volume>
   expands the volume to use all free extends
   or split up the additional size to several volumes

6) resize2fs /dev/mapper/<LVM-volume>
   to let the filesystem know about the additional space

Regards

Alexander

----- Original Message ----
> From: Eric B. <ebenze at hotmail.com>
> To: centos at centos.org
> Cc: linux-lvm at redhat.com
> Sent: Thu, February 18, 2010 6:11:26 PM
> Subject: [CentOS] Resizing a PV that belongs within a Volume Group?
> 
> Hi,
> 
> I was wondering if there was a way to extend (ie: grow) a PV that is part
of
> a Volume Group?  I currently have a partition on my HD that is being used
as
> a PV for my Volume Group, but would like to make it larger.  I have the
> space on my drive to extend my partition, but using standard tools (ex:
> gparted, Partition Magic, etc) would likely end up corrupting the data on
in
> the Logical Volumes that are housed within the VG.
> 
> I realize that I could just create a new partition on my HD and just add it
> to my Volume Group and extend my Volume Group, however, given that it would
> be two contiguous partitions on the HD, I was just wondering if there was a
> way of resizing the original partition within the VG without causing any
> problems.
> 
> I tried looking at tools like pvresize but I can't seem to understand
the
> right arguments to use it as whatever I try never seems to resize the 
> original partition itself.  I also looked at system-config-lvm GUI tool,
but
> that doesn't seem to allow me to make the PV any larger.
> 
> Does anyone have any suggestions?

First extend the physical media (resize the partition, LUN, whatever), then just
pvresize the new partition

Use with care, test it a few times in a test box or VM, then try it in
production, if you screw up you'll lose your data.

Or just do it simple... take the extra free space on the disk, create
a new partition there and add that as a new PV to the VG.


-- 
//Morten
//morten at mortent.org