On Mon, November 9, 2015 12:42 pm, m.roth@5-cent.us wrote:
Gordon Messmer wrote:
On 11/09/2015 09:59 AM, John R Pierce wrote:
On 11/9/2015 9:50 AM, Gordon Messmer wrote:
I don't see the distinction you're making.
a incremental backup copies everything since the last incremental a differential copies everything since the last full.
I guess that makes sense, but in backup systems based on rsync and hard links (such as rsnapshot), *every* backup on the backup volume is a "full" backup, so incremental and differential are the same thing.
rsync is NOT a backup system, its just a incremental file copy
..which can be used as a component of a backup system, such as rsnapshot or backuppc.
Actually, we use rsync for backups. We have a script that creates a new daily directory... and uses hard links to previous dates. That way, it looks like a full b/u... but you can go to a previous date to restore an older version of the file (aka ACK! I saved that file full of garbage to my Great American Novel filename! <g>).
I wonder how filesystem behaves when almost every file has some 400 hard links to it. (thinking in terms of a year worth of daily backups).
Valeri
And if you aren't familiar with hard links, which rsync happily creates, they were certainly hard enough to wrap my head around, until I got it... and really like them. Just note that they *must* be on one filesystem, as opposed to symlinks, which can cross filesystems.
mark
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++++++++++++++++++++++++++++++++++++++++ Valeri Galtsev Sr System Administrator Department of Astronomy and Astrophysics Kavli Institute for Cosmological Physics University of Chicago Phone: 773-702-4247 ++++++++++++++++++++++++++++++++++++++++