rsync is bad

Smoot Carl-Mitchell smoot at
Sun Jun 8 04:04:30 UTC 2008

On Sun, 2008-06-08 at 10:37 +0800, SYNass IT Ubuntu / Linux wrote:

> Thanks for your interesting links !
> However I / we already have a combined solution with rsync AND dd ...
> ... like you mentioned in the 2nd link but opposite in sequence:
> Daily's are rsynced and weekely's or higher's are additionally dd'ed !!

dd is not necessarily a good backup solution, since it is a byte for
byte copy of a physical or logical volume.  If the intent is to save a
*volume* then dd is a good choice.  But as a general backup solution, it
has shortcomings, since it is difficult to restore individual files and
impossible to restore the image to a different size disk, easily. 

As for rsync, I use it as a piece of a backup solution along with
glastree to do nearline incremental backups.  The big advantage of rsync
is it only copies incremental updates, so it can be very fast, if your
filesystem changes slowly.  I am not sure what Karl's specific issue was
with rsync, but depending on what his requirements are, it may not be
the appropriate tool. However, rysnc is not "bad".  In fact the
underlying algorithm is a beautiful and efficient piece of engineering.
However, one of the problems even the author of rsync admits is the
program suffers from option creep.  e.g. there are way to many options
and it can be confusing to understand what the all do and how they
interact which could lead one to the conclusion that the program is
somehow broken.
Smoot Carl-Mitchell
System/Network Architect
smoot at
+1 480 922 7313
cell: +1 602 421 9005

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