Re: Adding LVM to an existing system
Dick Davies wrote:
On 16/11/05, Marc Shapiro <email@example.com> wrote:
One thing that I have yet to see a conclusive answer to: Can I make LVM
Logical Volumes from logical partitions in an extended physical volume.
Since I have 4 physical volumes, including an extended volume, I would
have to create the LVs from logical partitions.
You sound a bit confused on the terminology.
A disk has 4 primary partitions, not 'physical volumes'. One of those is set
up as an extended partition (with lots of logical partitions in it, as you say).
Yes, I did confuse some of my terminology, but the question is still the
same: Can I create LVM physical volumes from logical partitions, and
Also, assuming that I can use logical partitions, is it possible to use
some, but not all logical partitions from an extended partition.
Currently, my / partition is /dev/hda5 and my /boot partition is
/dev/hda11 and I would want these to NOT be included in the LV.
1. run pvcreate on the logical partitions you want to use
2. vgcreate a volume group from them
2. chop it up with lvcreate to make some logical volumes
See the HOWTO, it's straightforward.
It's no different from adding extra swap, and won't touch your other partitions.
Well, apparently not. The HOWTO never actually says that you can, or
can not use logical partitions to make a physical volume. At least I
could not find it. However, when I tried to use pvcreate on a logical
partition it did not work:
root@xander:~# sfdisk -l /dev/hda
Disk /dev/hda: 77545 cylinders, 16 heads, 63 sectors/track
Warning: extended partition does not start at a cylinder boundary.
DOS and Linux will interpret the contents differently.
Warning: The partition table looks like it was made
for C/H/S=*/255/63 (instead of 77545/16/63).
For this listing I'll assume that geometry.
Units = cylinders of 8225280 bytes, blocks of 1024 bytes, counting from 0
Device Boot Start End #cyls #blocks Id System
/dev/hda1 * 0+ 649 650- 5221093+ 83 Linux
/dev/hda2 650 683 34 273105 82 Linux swap / Solaris
/dev/hda3 684 999 316 2538270 83 Linux
/dev/hda4 1000 4864 3865 31045612+ 5 Extended
/dev/hda5 1000+ 1031 32- 257008+ 83 Linux
/dev/hda6 1032+ 1044 13- 104391 83 Linux
/dev/hda7 1045+ 1174 130- 1044193+ 83 Linux
/dev/hda8 1175+ 1564 390- 3132643+ 83 Linux
/dev/hda9 1565+ 1694 130- 1044193+ 83 Linux
/dev/hda10 1695+ 2193 499- 4008186 83 Linux
/dev/hda11 2194+ 2200 7- 56196 83 Linux
/dev/hda12 2201+ 4864 2664- 21398548+ 8e Linux LVM
root@xander:~# pvcreate /dev/hda12
Device /dev/hda12 not found.
As you can see, pvcreate does not appear to want to work on /dev/hda12.
This was the case with partiton type 83 as well.