[Nottingham] Just how smart is rsync?

[Richard Dewhurst]

Or take the more sensible option of extracting the zip files on both 
ends and running rsync on the uncompressed images.

Rsync is perfectly capable of transferring only the changed portions of 
a large file, it's just that compressed files tend to change completely 
when the files inside change, unless created with something like gzip's 
--rsyncable.

It also has --compress/--compress-level if you want to compress the 
transfer itself.


Martin wrote:
> On 26 May 2011 16:21, Jason Irwin <jasonirwin73 at gmail.com> wrote:
>>> Is it one huge compressed image or is it rather small bits that contribute?
> 
> If the VMimage is compressed as one block, then rsync will see it as
> one file and will transfer it as one file.
> 
> If you can mount the image remotely, and mount your image locally,
> then rsync will only transfer the files and directories that are
> different between the two. Just to be sure, I'd use the "-c" option
> for checksumming but with 11 GBytes, you'll need fast machines for
> that to be practical in just 24 hours!
> 
> How fast is your connection?
> 
> Perhaps your only chance is to mount the contents of the images and
> rsync the difference of the contents of the images.
> 
> 
> Or...
> 
> Jump on an airplane with a memory stick?
> 
> Good luck,
> Martin
> 
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