few questions on rsync

Igor Lautar igor.lautar at gmail.com
Tue Jun 22 05:59:32 MDT 2010


I have few questions that could not find answers to in documentation.

Different filesystems:
Lets say I want to keep all extended attributes and everything else,
so I use -A, -X, --perms etc., together with --fake-super.
Now, lets say source FS supports some attributes not supported on
target FS (for example, XFS extended attributes). Would this work as
expected (ie. extended attributes are kept on target somehow)?

Reversing --backup logic:
Currently, if --backup is used (and --backup-dir), a copy of existing
file that is replaced on rsync will be placed there. Is there a way to
keep original copy (ie. base) the same, but just place whatever has
changed to a different location? Taking "backup to a central backup
server with 7 day incremental" example on rsync page, but reverse the
logic. Instead of current, you have 'initial' and then each
incremental only contains changed files from 'initial' (basically,
each incremental would then be differential, but thats besides the

delta-xfer algorithm:
Does delta-xfer detect change in following case:
lets say file contains data like "<data>", and is rsynced. Before next
rsync, file data changes to "<prefix><data>", where <prefix> is some
stream of bytes. Will rsync trasfer only <prefix> data (and detect
content has just moved in a file) or will whole file be transfered?

Saving delta-transmition stream:
Is it possible to save delta-transmition stream (or whatever rsync is
sending) as intermediate result? For example, save this stream, and
feed it later to another rsync that then applies it to base?

Basically, I'm interested if rsync stream can be somehow stored for
later use, to minimize number of files on disk (stream changes into
single file for example, put it to tape etc.). For example, tar could
be used to achieve this after rsync does its job, but I'm interested
in other possibilities.

Thank you for your answers,

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