Re: Speed Difference SCP vs. RCP

From: Nico Kadel-Garcia (nkadel_at_comcast.net)
Date: 01/25/05 

Date: Tue, 25 Jan 2005 04:21:09 -0500

"Michael" <michaeln@twentyten.org> wrote in message
news:10vb42vs0a1015a@corp.supernews.com...
> We're running network backups on the private LAN of our production
> network.
> We've grown to a point where our incremental backups are taking quite a
> long
> time. Our default transport method is SCP, but since it's the local LAN,
> I
> was wondering what this groups thoughts were on doing these backups over
> plain RCP. I consider our LAN secure, but I've also always been a fan of
> being secure whenever possible.

Bad! Bad! No sys-admin biscuit!

Don't use scp or rcp for backups, because they will duplicate the contents
of symbolic links rather than the link itself. It only takes one symbolic
link back up to / to explode your backup system.

Instead, use "rsync -e ssh -avvH --delete" to get all the links and delete
no-longer needed files, or consider using rsync as a directly accessible
protocol for a specific backup server if you think rcp is enough for your
internally secured network.

> In our speed tests, we push about 472 MB/min via SCP and 960 MB/min via
> RCP.
> Do these numbers (or at least ratios) seem right to you for a
> gigabit-over-copper network?

Yup. But try using rsync: You have a larger start-up cost, but you save huge
amounts of bandwith not duplicating files already present on the backup
system.

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