[linux-lvm] mounting a filesystem on LVM2
Stuart D. Gathman
stuart at bmsi.com
Tue Oct 5 14:25:12 UTC 2010
On Tue, 5 Oct 2010, Tapas Mishra wrote:
> On Tue, Oct 5, 2010 at 11:54 AM, Stuart D. Gathman <stuart at bmsi.com> wrote:
> > 3) an "LV" is a Logical Volume. An advanced user might want to use an
> > LV to simulate a disk, putting a partitional table on it. Usually
> > this is done by using the LV as a virtual disk for a Virtual Machine,
> > which then partitions and uses the virtual disk as it pleases.
> > You could also use fdisk/parted to partition an LV, and kparted to
> > make the partitions available as separate block devices.
> This is exactly what I am looking at.
> A tool virt-manager (from Red Hat does that)
> how does it do ?
> While installing a guest OS in an LVM I do not have to create a swap I
> just point to the ISO on my server
> and rest is done.
> How is that part taken care of does virt-manager do it or the OS which
> is being installed some thing from that makes sure that when you are
> installing a guest OS in a virtualization environment then in an LVM
> it will do.
> Because I never needed to create partitions within LVM until I am
> doing this setup to clone the LVM on the server to a
> USB backup drive.
1) man kpartx
2) "partitions within LVM" doesn't make sense. LVM is a software package,
not a storage device, and it doesn't do partitions.
You probably mean "partitions within an LV".
Here is an example of using kpartx:
# lvcreate -L1G -n test vg_sdg
# fdisk /dev/vg_sdg/test
# sfdisk -l /dev/vg_sdg/test
Disk /dev/vg_sdg/test: 130 cylinders, 255 heads, 63 sectors/track
Units = cylinders of 8225280 bytes, blocks of 1024 bytes, counting from 0
Device Boot Start End #cyls #blocks Id System
/dev/vg_sdg/test1 0+ 99 100- 803218+ 83 Linux
/dev/vg_sdg/test2 100 129 30 240975 82 Linux swap / Solaris
/dev/vg_sdg/test3 0 - 0 0 0 Empty
/dev/vg_sdg/test4 0 - 0 0 0 Empty
# kpartx -l /dev/vg_sdg/test
vg_sdg-test1 : 0 1606437 /dev/vg_sdg/test 63
vg_sdg-test2 : 0 481950 /dev/vg_sdg/test 1606500
# kpartx -av /dev/vg_sdg/test
add map vg_sdg-test1 (253:6): 0 1606437 linear /dev/vg_sdg/test 63
add map vg_sdg-test2 (253:7): 0 481950 linear /dev/vg_sdg/test 1606500
# mke2fs /dev/mapper/vg_sdg-test1
mke2fs 1.41.9 (22-Aug-2009)
OS type: Linux
Block size=4096 (log=2)
Fragment size=4096 (log=2)
50288 inodes, 200804 blocks
10040 blocks (5.00%) reserved for the super user
First data block=0
Maximum filesystem blocks=209715200
7 block groups
32768 blocks per group, 32768 fragments per group
7184 inodes per group
Superblock backups stored on blocks:
32768, 98304, 163840
Writing inode tables: done
Writing superblocks and filesystem accounting information: done
This filesystem will be automatically checked every 29 mounts or
180 days, whichever comes first. Use tune2fs -c or -i to override.
# mount /dev/mapper/vg_sdg-test1 /mnt/tmp
Filesystem 1K-blocks Used Available Use% Mounted on
/dev/dm-1 15481840 12143008 2552400 83% /
tmpfs 512672 404 512268 1% /dev/shm
/dev/sda1 295561 95222 185079 34% /boot
/dev/dm-0 36124288 31419784 2869688 92% /home
/dev/dm-3 10321208 5969640 3827324 61% /video
/dev/sr1 6828 6828 0 100% /media/U3 System
/dev/sdb1 7837760 2046560 5791200 27% /media/Cruzer
790556 808 749588 1% /mnt/tmp
Stuart D. Gathman <stuart at bmsi.com>
Business Management Systems Inc. Phone: 703 591-0911 Fax: 703 591-6154
"Confutatis maledictis, flammis acribus addictis" - background song for
a Microsoft sponsored "Where do you want to go from here?" commercial.
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