[Fedora-xen] Createing/working with disk images

[Lamont Peterson]

On Tuesday 27 March 2007 03:42pm, Karel Zak wrote:
[snip]
> > How can I access partitions inside a disk image as block devices?  Should
> > I be using something other than losetup here?
>
>  man losetup
>  man mount
>
>  ... option "offset"

Yeah, the moment I sent the original post, I realized I could try using 
offsets with losetup.  Unfortunately, it's not quite working.

I think the problem is that the -s switch won't work with the RHEL5 or FC6 
loopback drivers and without it, running:

# losetup -o512 /dev/loop1 /some/image/file

... is creating /dev/loop1 to span from the beginning of partition 1 to the 
end of the image file, which includes the space for partitions 2 and up.  
The -s switch needs to be used here to make this loopback device the right 
size.

The note, "This option may not be supported on some older kernels and/or loop 
drivers," appears in the losetup(8) man page with the -s information.  I 
don't think these would be considered "older kernels" but the losetup command 
is not able to work when I try to use -s.

>  or you can try lomount (from the Xen package) that supports
>  partitions more friendly. For more information (especially when you
>  want to use LVM), see:

That's good to know about.  Of course, that will only work once there is a 
filesystem on the partition inside the image file.  I still have the problem 
of being able to run mke2fs and format *just* the partition within the image.

> 
> http://fedoraproject.org/wiki/FedoraXenQuickstartFC6?highlight=%28Xen%29#he
>ad-9c5408e750e8184aece3efe822be0ef6dd1871cd

Thanks.
-- 
Lamont Peterson <lamont at gurulabs.com>
Senior Instructor
Guru Labs, L.C. [ http://www.GuruLabs.com/ ]

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