Full clone of thin drive doesn't shrink

robnicholson · Tue Oct 04, 2011 12:24 pm

Okay, so the clue might be in the "full clone" bit but I've just done a full clone of a 40.2GB growing image (thin provisioning) disk and the clone is also 40.2GB big. This kind of caught me by surprise as I'm used to using full clone in VMware workstation where the cloned image is only as big as the number of used blocks. In effect, cloning can be used to shrink the drive.

Does StarWind not do something similar?

Cheers, Rob.

PS. I know I asked about on the fly shrink but this is an offline shrink operation during clone.

robnicholson · Tue Oct 04, 2011 12:25 pm

And also, the percentage bar doesn't work. Appears on-screen at 50% and stays there throughout the whole clone operation. Only way to check progress is to look at the disk in Explorer and keep hitting refresh watching the size go up.

Cheers, Rob.

Thu Oct 06, 2011 9:29 am

Could you please clarify if you are using the lates version of StarWind (it is 5.7.1733)?
You have Thin Provisioning, that means that devise size equals to the size of the data written on it. So that is why there behaviour that you`ve described is totally expected. One little thing for you to note: StarWind is not analyzing host file system, so if you`ll delete the data from StarWind device it will not decrease the size of the device.

robnicholson · Thu Oct 13, 2011 3:45 pm

Hi Anatoly,

We're on v5.7.1733 which yes, latest version. Yes, it's probably because StarWind is blind to the host file system that it is unable to identify which blocks are currently free and therefore could be compacted during a clone. I assume all it knows is whether a particular block has been written to at some point and uses this to add new blocks on the end.

So one must assume that the tools that can shrink/compact during clone do interrogate the host file system and make changes to the directory structure during the clone. And yes, I can appreciate that this is a more dangerous operation.

One maybe for the wish list with the top-5 common disk formats like NTFS and EXT-3?

We might be able to do something creative with Acronis Backup & Recovery which can re-size partitions during a restore.

Cheers, Rob.

Fri Oct 14, 2011 11:15 am

Thank you for the idea! I think it will be it will be implemented in future releases.