[nylug-talk] rsync daemon or ssh ?

[Adrian Sai-Wah TAM]

My $0.02: If you're doing the backup frequently, consider
unison---this make hash computation local as much as possible, and
keeps a state on what is last backed up.

Unison: http://www.cis.upenn.edu/~bcpierce/unison/

- Adrian.

On Thu, May 1, 2008 at 4:34 PM, Brian Mathis
<bmathis-nylug at directedge.us> wrote:
> 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
>  >>
>  >>
>  >>
>  > [...]
>  >
>  >
>
>
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