Re: [PATCH]: Support dynamic resizing of vbds

[Andrew Lyon <andrew.lyon@gmail.com>]

On Fri, Mar 12, 2010 at 10:41 AM, J. Roeleveld <joost@antarean.org> wrote:
> On Tuesday 09 March 2010 20:56:11 Ky Srinivasan wrote:
>> The attached patch supports dynamic resizing of vbds.
>>
>> Signed-off-by: K. Y. Srinivasan <ksrinivasan@novell.com>
>>
>
> Thank you for this.
>
> The patch applied succesfully against the gentoo-xen kernel (2.6.29-xen-r4)
>
> I will test the patch on my system during the next week and provide feedback.
>
> --
> Joost Roeleveld
>
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I tested the patch on xen-sources-2.6.31-r12 and it appears to work perfectly:

dom0: VBD Resize: new size 172032
domU: Setting capacity to 172032

I extended the filesystem and filled up the available space, then
extended again:

dom0: VBD Resize: new size 376832
domU: Setting capacity to 376832

fsck, badblocks, and testing a tarball I had filled the filesystem
with revealed no problems, so I decided to try reducing the
filesystem, first using resize2fs, then reducing the size of the block
device, although some errors were logged in domU the operation seemed
to work ok:

dom0: VBD Resize: new size 114688
domU: Setting capacity to 114688
domU: end_request: I/O error, dev sdb1, sector 212984
domU: Buffer I/O error on device sdb1, logical block 26623

I did notice that it seemed to be necessary to "poke" the device using
cfdisk /dev/sdb1 before domU would notice the new size, but on the
whole everything works nicely and this is a very useful new feature!

Andy