[linux-lvm] Moving space between logical volumes?
Meadows, Howard T
howard-meadows at uiowa.edu
Tue Sep 6 15:18:10 UTC 2005
On Tue, 2005-09-06 at 9:22 AM, David Johnston wrote:
>
>e2fsadm is a front end for the LVM tools. It simplifies things by doing
>the math for you, and by doing the steps in the correct order (which
>changes depending on whether you are growing or shrinking).
>
>If /dev/vg/lv1 and /dev/vg/lv2 are logical volumes, and you have ext3
>filesystems on them, all you need to do is this:
>
># Shrink lv1
>umount /dev/vg/lv1
>e2fsadm -L -100G /dev/vg/lv1
>mount /dev/vg/lv1
>
># Expand lv2
>umount /dev/vg/lv2
>e2fsadm -L +100G /dev/vg/lv2
>mount /dev/vg/lv2
>
>That's it.
>
>I'm concerned about your reference to /dev/sda5. Is that your LVM
>partition? If so, leave it alone. From its name, it's clear that it is
>not a logical partition, so you can't use LVM tools to manipulate it.
>What's special about /dev/sda5 that makes you think you need to turn
>journaling off before you can resize /dev/vg/lv1?
>
>-DJ
>
>LVM vocabulary in newbie terms:
> physical volume = a disk
> logical volume = a partition
>By extention,
> lvresize = fdisk
>
>In reality, it's not that simple, but until you're comfortable with LVM,
>these simple definitions will steer you well.
>
David,
Thanks very much for the information.
To clarify my present configuration, I'm including data from fdisk,
vgdisplay and lvdisplay for the two logical volumes I want to resize.
From what I see, it sounds like I can use the commands you specified
(with the correct lv and vg names) and all should be well (with no loss of
data). If I could take advantage of your kindness just a little more, could
you look at my information below and confirm that those commands are
correct?
Thanks VERY much,
-Howard
Here is the data:
=====================================
Data reported with fdisk p command:
Disk /dev/sda: 254 heads, 63 sectors, 44798 cylinders
Units = cylinders of 16002 * 512 bytes
Device Boot Start End Blocks Id System
/dev/sda1 * 1 3 23971+ 83 Linux
/dev/sda2 4 259 2048256 83 Linux
/dev/sda3 260 514 2040255 82 Linux swap
/dev/sda4 515 44798 354316284 5 Extended
/dev/sda5 515 770 2048224+ 8e Linux LVM
/dev/sda6 771 32767 256007965+ 8e Linux LVM
=======================================
Output from vgdisplay command for
volume group containing logical
volumes in question:
# vgdisplay /dev/storagevg
--- Volume group ---
VG Name storagevg
VG Access read/write
VG Status available/resizable
VG # 1
MAX LV 256
Cur LV 4
Open LV 4
MAX LV Size 2 TB
Max PV 256
Cur PV 2
Act PV 2
VG Size 585.88 GB
PE Size 32 MB
Total PE 18748
Alloc PE / Size 18208 / 569 GB
Free PE / Size 540 / 16.88 GB
VG UUID Ntjcgr-zTVs-Lp6e-Tvrj-HU9u-ZcCq-cY10Lv
====================================
Output from lvdisplay command for the logical
volume I want to reduce by 100 GB:
# lvdisplay /dev/storagevg/atdevel
--- Logical volume ---
LV Name /dev/storagevg/atdevel
VG Name storagevg
LV Write Access read/write
LV Status available
LV # 1
# open 1
LV Size 505 GB
Current LE 16160
Allocated LE 16160
Allocation next free
Read ahead sectors 1024
Block device 58:4
=================================
Output from lvdisplay for logical
volume I want to increase by 100 GB:
# lvdisplay /dev/storagevg/gcg
--- Logical volume ---
LV Name /dev/storagevg/gcg
VG Name storagevg
LV Write Access read/write
LV Status available
LV # 4
# open 1
LV Size 50 GB
Current LE 1600
Allocated LE 1600
Allocation next free
Read ahead sectors 1024
Block device 58:1
===============================
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