Re: comparison of star and rsync methods

Lasse Kliemann wrote:
>  
> So the real competitors are 'rsync S --> V' and 'star S' (hoping that the 
> problems with the latter can be resolved). Clearly, star is faster than 
> rsync; the star runs only take about 60% of the time of the rsync runs.

I think your results with rsync will vary with the number of files in 
the run, and with -H also with the number of hard links.  Rsync will 
read the entire directory contents with a certain amount of RAM overhead 
per file before starting.  If you have a few big files, that's not a 
problem - with a lot of tiny files it can be noticeable.  I think the 
very latest version may start the comparison before the full directory 
load completes, at least when running over a network, though.

> The 
> big structural difference is that with rsync, one has the backup in a 
> filesystem instead of in a single file (or in few files with incremental 
> dumps). This can be an advantage if one often has to access particular files 
> in the backup. It can also be a disadvantage if one wishes to write the 
> backup to some external medium or push it over the network.

Actually the way rsync works can be a big advantage when writing over a 
network that is slow compared to the disks.  You can use the -z option 
for compression, and it will walk through the file doing block checksum 
compares with the existing remote copy, sending only the changed parts 
for the remote to assemble.

-- 
   Les Mikesell
    [email protected]