Roberto Ragusa wrote:
Craig White wrote:
I was able to reduce the size of the logical volumes, move the logical volumes so they are adjacent and then reduce the size of the physical LVM but I cannot seem to reduce the partition itself and I'm gathering that this may not be possible.
# pvdisplay --- Physical volume --- PV Name /dev/sda2 VG Name VolGroup00 PV Size 95.00 GB / not usable 31.81 MB Allocatable yes PE Size (KByte) 32768 Total PE 3039 Free PE 127 Allocated PE 2912 PV UUID oAYcCQ-5n28-0C6i-1LLE-voCR-E19v-SQYQK0
# fdisk -l /dev/sda
Disk /dev/sda: 203.9 GB, 203928109056 bytes 255 heads, 63 sectors/track, 24792 cylinders Units = cylinders of 16065 * 512 = 8225280 bytes Disk identifier: 0x00086350
Device Boot Start End Blocks Id System /dev/sda1 * 1 13 104391 83 Linux /dev/sda2 14 24792 199037317+ 8e Linux LVM
# df -h Filesystem Size Used Avail Use% Mounted on /dev/root 88G 54G 30G 65% / /dev/sda1 99M 36M 59M 39% /boot
so in the end, /dev/sda2 remains approximately 200G and even the gpartd-liveCD cannot resize /dev/sda2 ;-(
Is it even possible?
What you are attempting is not a common way to use the LVM system. I often create many pv on one disk (sda2, sda3, sda4) just to avoid this kind of problems.
The pv is now 95G, so only the first 95G of sda2 are used (usable). Now, thinking about it, resizing sda2 could simply mean you have to delete and immediately recreate sda2 with a smaller size. We just have to be sure about where the pv metadata are stored. According to
http://www.guug.de/lokal/rhein-main/2004-09-23/LVM2_sage_23.09.pdf
we learn that
LVM2 format is an ASCII text format which is at the beginning, after a disk label, of every PV in 2 copies by default in large configurations...
so it is at the beginning of the pv.
The procedure I'd try (assuming I had a backup of everything, as _this is obviously dangerous_):
- Boot from CD and without any kind of lvm detection.
- Destroy sda2 and recreate it as 100G.
- Boot the system again, check that the LVM is OK and
pvresize sda2 in automatic size (so it goes from 95G to 100G).
Step 3) avoids that you have to calculate the new size for sda2, which is very difficult because of the partition and LVM roundings.
If you find the courage to try this, let me know how it went.
:-)
---- OK - makes sense and thanks for the concept.
By the way...in studying information on parted, it appears that it is not capable of resizing an LVM partition...which explains why I couldn't get anything done beyond lvresize/pvresize.
I'm currently backing up everything - which I probably should have done before I ever started but clearly, the steps you outline go beyond a simple leap of faith. Unfortunately, I am using a USB disk so the backup is quite slow - c'est la vie
To back up, I booted from CD #1 in rescue mode and am using the following command...
cp -ar /mnt/sysimage/* /mnt/usb
Does anyone think that there is a problem with this type of logic for backup in terms of preserving linked files, etc?
Obviously I will have all my user files so a complete wipe and clean re-install will only suck time but no important data and I've done it this way in the past but I keep wondering if I should have tar'd everything to the USB disk instead
Thanks
Craig