[Date Prev][Date Next] [Thread Prev][Thread Next] [Date Index] [Thread Index]

Re: Adding LVM to an existing system

Dick Davies wrote:
On 16/11/05, Marc Shapiro <mshapiro_42@yahoo.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.

That's fine.

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.

Marc Shapiro

Reply to: