[Libguestfs] [PATCH FOR DISCUSSION ONLY] virt-resize tool for resizing virtual machines.

[Richard W.M. Jones]

On Sun, Mar 21, 2010 at 07:08:26PM +0100, Dennis Krul wrote:
> I think that, in the case of LVM, you should just concentrate on  
> resizing the PV's and the partitions they're on. That probably makes  
> things a lot easier :)
>
> If the user wants to expand an image, then simply resize the partition  
> and run pvextend. Or alternatively add a new partition, run pvcreate and 
> add it to the volume group.
>
> If a user wants to shrink an image, he simply needs to ensure enough  
> free space is available within the VG for the virt-resize operation to  
> succeed.

Yup, I think I agree, especially in the expand case.  Shrinking _is_
more complex (but much rarer in practice) because in that case we have
to check that the PV is small enough already.

> The only use case that causes problems is if the user has all VG space  
> consumed by filesystems that cannot be unmounted for shrinking the  
> filesystem (read: root). But in that case there is little point in using 
> LVM anyway :)

They can do this offline with guestfish, although it's all horribly
manual.

I think there's some case for not concentrating too hard at the moment
on the shrink case, since I'm betting that is rare.  I'll wait for
users to request it before doing a more thorough implementation.

Rich.

-- 
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