Ubuntu – Why are Ubuntu One files in the cloud not the same size as the original

ubuntu-one

I tar ~/Documents to create backups. My .tgz files are approximately 700MB. I have created three such files over the past 3 weeks and I used Ubuntu One to protect these from loss. In all three cases, the file size reported on the Ubuntu One website does not agree with the file size reported by Nautilus. In all three cases, the file size in the cloud is several MB smaller than the one on the desktop file system.

Example: My 2012 May 10 backup is 761MB but on the cloud it is 726MB.

Why is this happening?

Best Answer

Ubuntu One uses zlib to compress data before sending it, to save some bandwidth when doing the transfer. It also stores the file content in the compressed form on the server, to avoid having to recompress it before sending it back down the stream.

The answer has nothing to do with file system block sizes.

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