[linux-lvm] mounting a filesystem on LVM2

[Tapas Mishra]

On Tue, Oct 5, 2010 at 7:55 PM, Stuart D. Gathman <stuart at bmsi.com> wrote:
> 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)
> Filesystem label=
> 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
> # df
> 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
> /dev/mapper/vg_sdg-test1
>                        790556       808    749588   1% /mnt/tmp
I was about to reply but you posted it first.
By  the time  your message came I had been able to do it by steps
similar to what you mentioned above.