[CentOS] Proper partition/LVM growth after RAID migration

[Johnny Hughes]

On Tue, 2006-10-17 at 06:00 -0500, Johnny Hughes wrote:
> 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 ... 
> http://episteme.arstechnica.com/eve/forums/a/tpc/f/96509133/m/839007490831
> 
> (that is not what I recommended, but something I found on google)
> 

Just a note ... looks like pvresize can be used to extend the PV after
the partition is extended.
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