[Dirvish] Tips for low-bandwidth backups

[ml-it-dirvish at epigenomics.com]

On 6 Aug 2007 02:41:53 -0700,
 "Asheesh Laroia" <asheesh at asheesh.org> wrote:
> On Mon, 6 Aug 2007, Dave Howorth wrote:
>
>> There used to be a saying that the highest bandwidth link between London
>> and Manchester was a van full of tapes. I suspect it's still true. The
>> obvious suggestion is to carry the initial image on tape or disk rather
>> than use a slow network connection. But if you don't want to do that ...
>
> The initial image is done, it's just that the other site generated a lot 
> of data that should get backed up.  Most days there will be a tiny 
> differential, but some days there will be a huge differential - so big 
> that it could take around a week to push it all up.

Use the pre-server and post-server scripts.

In the pre-server script check for a lockfile.

If it exists, exit the pre-server script so that this dirvish run will
fail.

If it does not exist, create it and let dirvish do its backup.

In the post-server script, remove the lockfile.


It's a classical binary semaphore: http://en.wikipedia.org/wiki/Semaphore_%28programming%29

Greetings
-- 
Robert Sander                     Senior Manager Information Systems
Epigenomics AG    Kleine Praesidentenstr. 1    10178 Berlin, Germany
phone:+49-30-24345-0                            fax:+49-30-24345-555
http://www.epigenomics.com             robert.sander at epigenomics.com