Long time needed for "Building file list" Any suggestions ?

[Jim Salter]

No.  Rsync has to build a list of *every single file in the filesystem*, 
along with - at a minimum - last modified datestamp.  Rsync needs to be 
able to propagate deletions if necessary, and to do that, you have to 
compare the entire list of all files (not specifically excluded) in the 
specified section on both volumes, not just the changed ones.

Also keep in mind that while if you're using the find / -ctime trick, 
YOU can assume that the other end is a mirror and you know exactly when 
the last time it was synchronized was, rsync knows no such thing.  Rsync 
  *produces* a mirror whether or not it started out with one.

Jim Salter

> But isn't building this exact file list what an ordinary call to rsync 
> is supposed to do (when not forcing checksum calculation)? So why is 
> rsync so much slower than find?
> 
> /Greger
> 
> Tim Conway wrote:
> 
>> Good idea
>> find / -ctime -1h |rsync -a --files-from=- / destination
>> No perl needed.  You might want mtime instead, though.
>>  
>>
>>  
>>