rsync from tar

[Todd Rinaldo]

I use rsync to backup an application's file system state to a
repository. Later if we want to refresh a test environment with the
application's file state at that given point in time, we can use rsync
to get the test environment into that state.

Rsync works well for this purpose, but it would be nice if we could
rsync to/from a tar (or other archive format) file. Since our use of
rsync is to store these FS copies for sparse use, it's cumbersome to
have the files stored unarchived since there are alot of files, not to
mention they cannot be compressed if they are left in their original
state.

Tar without rsync is not an option here because we need file deletion,
as well as updating new/exisiting files. Tar also updates files even
if they have not changed, which puts an undue burden on our file
systems' snapshot systems since it then looks like every single file
has changed (new inode), rather than only a hand full.

My idea for a solution here would be a new feature to the rsync daemon
mode that would write out files to an archive format, rather than a
target file system.  I'm curious if anyone could suggest an
alternative approach and/or if there is interest in this feature
within rsync.

Thanks,
Todd