Database file rsync - any way to tell it to rsync against the last file?

Michael Bourgon bourgon at
Fri Nov 12 21:27:57 GMT 2004

My apologies if this has been asked before - I searched the archives
but couldn't find it, probably because I'm not sure what terms to use.

I'm trying to rsync database backups from point A to point B, where
point B has rsync running as a service.

Every day I make a new backup on point A (mike_db_20041110.bak), and
since there's no matching file on point B, the entire file is sent
over.  But since these are backups of the same database, the
difference between mike_db_20041110.bak and the prior backup,
(mike_db_20041109.bak), should be fairly minor.

Is there any way to tell it that I want to rsync mike_db_20041110.bak,
using mike_db_20041109.bak as a source, so that when I'm done I still
have both files?  I could build a script to rename them to the same
filename, but I'd rather let rsync do the work if possible.

Thanks for the help.  I've been using Rsync for our backups for a year
now, and absolutely love it.  Now that the backups are getting bigger,
it's time to get more aggressive.


p.s. one other question - I know that Rsync compresses the file, but
does it look at the whole file first, then send?  The speeds I'm
getting sending these bak files doesn't look like it's being
compressed - the end file grows by about 10mb a minute, which is far
less than we should get with our T1.  And if it looks at the whole
file first, I should be seeing 10-to-1 compression.


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