[nylug-talk] rsync daemon or ssh ?

[Brian Mathis]

AFAIK (also not an rsync expert), rsync on both sides calculates the 
hashes on each respective side.  'rsync' running on hostA gets its list 
of hashes, and 'rsync' running on hostB gets its list of hashes.  Then 
they exchange and compare to see what needs to be transferred.  If you 
use --verbose when running, you can see that it probably does this 
file-by-file, as it doesn't print the output all at once at the end.

You'll have to look at a 'ps' listing or something to see the memory 
it's using at any given point.

-Brian Mathis

PS. If running interactively, --progress is also a nice option to use


Henning Follmann wrote:
> On Thu, May 01, 2008 at 03:35:13PM -0400, Brian Mathis wrote:
>   
>> In both cases, rsync runs on both of the servers.  The difference is 
>> that over ssh the communication is secure, and, AFIAK, as a daemon it's 
>> not.  Daemons would usually be used if you are running some sort of a 
>> software distribution server that you want to give public access to -- 
>> not really the sort of thing you'd use for file backups.
>>
>>     
> So if rsync runs on both sides (which i just confirmed - I din't know
> that). Which of the two daemons builds the hash for the files?
> Or are the two hold a copy of it?
> If we are talking 100 bytes / file * 1.7 * 10**6 we are talking about
> 170 MB for this process, right? 
> Hmm don't like that - but after all I was doing the same thing before.
>
>
>   
>> Using SSH is just fine, and in this case, using an rsync daemon is 
>> unnecessary.  I think the speed would be similar.
>>
>> -Brian Mathis
>>
>>
>>     
> [...]
>
>