[openstack-dev] [Nova][BluePrint Register] Shrink the volume when file in the instance was deleted.
john at johngarbutt.com
Thu Jan 2 14:54:13 UTC 2014
On 25 December 2013 05:14, Qixiaozhen <qixiaozhen at huawei.com> wrote:
> A blueprint is registered that is about shrinking the volume in thin
Have you got the link?
> Thin provision means allocating the disk space once the instance writes the
> data on the area of volume in the first time.
> However, if the files in the instance were deleted, thin provision could not
> deal with this situation. The space that was allocated by the files could
> not be released.
> So it is necessary to shrink the volume when the files are deleted in the
In this case the user will probably need to zero out the free space of
your filesystem too, in some cases, unless nova does that for them,
which sounds a bit dodgy.
> The operation of shrinking can be manually executed by the user with the web
> portal or CLI command or periodically in the background.
I wondered about an "optimise disk" call.
A few thoughts:
* I am not sure it can always be done "online" for all drivers, may
need an offline mode
* Similar operations have ways of confirming and reverting to protect
* Ideally keep all operations on the virtual disk, and no operations
on its content
* With chains of disks, you may want to simplify the chain too (where
it makes sense)
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