taking lvm backup

[Clint Byrum]

On Sep 27, 2010, at 10:30 PM, Tapas Mishra wrote:

> 
> 
> --- Logical volume ---
>  LV Name                /dev/nintendo/lvm4
>  VG Name                nintendo
>  LV UUID                y3I7sC-S2vn-huo0-CaGu-W7cF-duIR-B8fKWP
>  LV Write Access        read/write
>  LV Status              available
>  # open                 1
>  LV Size                100.00 GiB
>  Current LE             25600
>  Segments               1
>  Allocation             inherit
>  Read ahead sectors     auto
>  - currently set to     256
>  Block device           251:3
> 
> 
> 
> but when I go to directory
> /dev/nintendo I see the files
> total 0
> lrwxrwxrwx 1 root root 28 2010-08-27 10:58 lvm4 -> ../mapper/nintendo-lvm4
> lrwxrwxrwx 1 root root 33 2010-09-14 14:51 lvm3 -> ../mapper/nintendo-lvm3
> lrwxrwxrwx 1 root root 31 2010-08-27 10:58 lvm2 -> ../mapper/nintendo-lvm2
> lrwxrwxrwx 1 root root 33 2010-08-27 10:58 lvm1 -> ../mapper/nintendo-lvm1
> 
> of only zero bytes.
> 

These are just the symlinks to the device nodes. If you look in
/dev/mapper, you'll see type "b" files nintendo-lvm1, nintendo-lvm2,
etc.

These block devices have their size defined by LVM, which you can
see in 'lvdisplay' from above as "LV Size".

Do they have filesystems on them?

For each one, try something like:

mount /dev/nintendo/lvm4 /mnt -o ro

If it has a filesystem on it, that should detect it, and mount it
readonly, and you should be able to back up only what is *used* on
the volume, not the whole thing. Then just use whatever your favorite
backup method is.