restoring incremental backups

Keith Lofstrom keithl at
Wed Jun 15 16:55:47 GMT 2005

On Tue, Jun 14, 2005 at 04:11:07PM +0200, Erik Romijn wrote:
> Unfortunatly rsnapshot does not do what I need.
> The backups should be pushed by the fileserver to the backup server.
> This does not appear to be possible with rsnapshot, as far as I can find
> it only supports 'pulling' backups from remote hosts.

I manage another rsync-based disk-to-disk backup program, dirvish
(, originally written by jw schultz).  Rsnapshot and
dirvish and most other backup programs use server pull for a number
of sensible reasons:

1)  Security:  Backup clients can be compromised, and should have no
ability to initiate reads or writes to the server.

2)  Network load management: A backup server can coordinate and
sequence multiple backups much better than clients can.

3)  Disk management:  A backup server should manage its own disks.

You can achieve the functional equivalent of client-initiated backup
by signalling from the client to the server that backups should happen,
or flag a file on the client that is polled by the server.  You can
write simple scripts to do that for dirvish or for rsnapshot.  But
after that, the server should control the process.  Since an important
reason to do backups is to survive security penetration, bypassing
these protections reduces the value of backups.


Keith Lofstrom          keithl at         Voice (503)-520-1993
KLIC --- Keith Lofstrom Integrated Circuits --- "Your Ideas in Silicon"
Design Contracting in Bipolar and CMOS - Analog, Digital, and Scan ICs

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