[CentOS] Proper partition/LVM growth after RAID migration

Johnny Hughes mailing-lists at hughesjr.com
Tue Oct 17 11:00:18 UTC 2006

On Tue, 2006-10-17 at 08:11 +0200, Christian Wahlgren wrote:
> On 10/16/06, Shawn K. O'Shea <shawn at ll.mit.edu> wrote:
> >
> > > I did a RAID migration on a 3Ware 9590SE-12, so that an exported disk
> > > grew from 700GB to 1400GB. The exported disk is managed by LVM. The
> > > problem now is that I don't really know what to do now to let LVM and
> > > my locigal volume to make use of this new disk size, and probably
> > > future disk size growth.
> > >
> > I've been doing this recently with VMWare ESX server. To save space, I
> > create base disk images of clean OS installs on a minimalistic sized
> > disk. If I need space, I use tools from VMWare to make the virtual disk
> > bigger, and then grow the bits inside Linux with LVM.
> (...) (thanks for the links!)
> > To summarize the links...(usual caveats, backup data, etc, etc)
> > -Create  a new partition of type 8e (Linux LVM) on the new empty space.
> >
> > -Add that pv to LVM
> >  If the new partition is /dev/sda3, then this would look like
> > pvcreate /dev/sda3
> This part is actually the main question I had (in the Subject) - each
> time I add a disk to my RAID-5 volume on the RAID card, the exported
> disk is getting bigger. And every time I do this I have to add a
> partition on this disk to use this new space. With primary partitions
> I can only repeat this 4 times.
> So, is it the "proper way of doing this" when you grow this exported
> disk, to add partitions in a extended partition table each time you
> add a disk, and then add that PV partition to the VG, resize LVs etc?
> Compare to when you add a physical disk "directly" to a VG, you only
> create one partition on each new disk and then let your VG and LV to
> grow. This other situation with a RAID card you make one exported disk
> larger each time you add one or more physical disks to the RAID volume
> and then have to add a new partition on the same (emulated) disk (to
> the BIOS and operating system).

I have never tried this ... however, you can extend the size of a
partition with fdisk by removing partition and starting it on exactly
the same cylinder that it started before and ending at a larger
cylinder.  (Please test this on a partition that you can afford to
lose :)

I don't know how (or if) that effects the pv size that was assigned that
partition, but I do know that the file system stays the old size and
needs to be extended if it is non pv.

Here is something else I see ... 

(that is not what I recommended, but something I found on google)

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