[linux-lvm] lvextend for striped volume extension

[Alasdair G Kergon]

On Fri, Nov 22, 2002 at 01:21:37PM +0100, Heinz J . Mauelshagen wrote:
> On Wed, Oct 30, 2002 at 03:30:09AM +0900, shlim wrote:
> > Current LVM version support the lv extension for STRIPED VOLUME ??
> LVM1 is limited: you can't extend a stripe beyond a physical volume.
> Give LVM2 a try which doesn't suffer from this constraint unless
> you stay with the LVM1 ondisk format.

And when using the new metadata format in LVM2, 'lvextend' accepts the 
same stripe parameters as 'lvcreate'.  If the number of stripes and/or
stripesize aren't given, it uses the values used by the last segment
of the existing LV.

A simple example:

lvm> lvcreate --stripes 3 --extents 12 vg1
lvm> lvextend --stripes 2 --extents +12 vg1/lvol0
lvm> lvdisplay --maps

  --- Segments ---
  Logical extent 0 to 11:
    Type		striped
    Stripes		3
    Stripe size		32
    Stripe 0:
      Physical volume	/dev/sdb1
      Physical extents	0 to 3
    Stripe 1:
      Physical volume	/dev/sdb6
      Physical extents	0 to 3
    Stripe 2:
      Physical volume	/dev/sdb7
      Physical extents	0 to 3
   
  Logical extent 12 to 23:
    Type		striped
    Stripes		2
    Stripe size		32
    Stripe 0:
      Physical volume	/dev/sdb1
      Physical extents	4 to 9
    Stripe 1:
      Physical volume	/dev/sdb6
      Physical extents	4 to 9

And you can still specify a restricted list of PVs in the VG to use:
lvm> lvextend --stripes 2 --extents +12 vg1/lvol0 /dev/sdb6 /dev/sdb7

Alasdair
-- 
agk at uk.sistina.com