From: Richard Jones <rjones@redhat.com>
Date: Sat, 16 May 2009 07:45:14 +0000 (+0100)
Subject: To-do: Explain the situation with resizing block devices.
X-Git-Tag: 1.0.26~3
X-Git-Url: http://git.annexia.org/?a=commitdiff_plain;h=af7e3fc047447ff77ade4640194f9ec519068951;p=libguestfs.git

To-do: Explain the situation with resizing block devices.
---

diff --git a/TODO b/TODO
index 71c9d59..323dc0b 100644
--- a/TODO
+++ b/TODO
@@ -27,3 +27,25 @@ Implement febootstrap command.
 ----------------------------------------------------------------------
 
 Complete the Haskell bindings (see discussion on haskell-cafe).
+
+----------------------------------------------------------------------
+
+Practically, resizing the partitions when a block device is resized
+isn't possible.  So for example it's not possible to resize a Fedora
+block device.  If you try to use sfdisk-N to change the boundaries of
+the existing partition to fill up the new space, you get an error that
+the partition is in use.
+
+The reason, I now think, is because LVM is using the partition as a
+PV, and this locks it as far as the kernel is concerned.
+
+Removing the PV [which is what we do in the test suite] isn't
+desirable if the PV contains data you care about.  Rebooting the qemu
+subprocess after the partition table change works, but isn't very
+cool.  I believe what we need to do is to temporarily reconfigure LVM
+(using /etc/lvm/lvm.conf) to ignore the PV, vgscan (which will then
+ignore the PV), make the changes to the partition table, then set the
+LVM configuration back and do a final vgscan.
+
+Need to test the above, and find a nice way to present it through
+the API.