[nSLUG] rsync questions

Daniel MacKay daniel at bonmot.ca
Fri Feb 25 12:58:05 AST 2011

Almost a decade ago, I was planning to run a business based on rsync.  It was going to be a remote backup service for Macs.  

The elements were: 
* a script & cronjob on the customer Macs, and
* a disk farm in a machine room.

To do the backups, the script would run a vanilla rsync back to the disk farm (running the rsync daemon.)  rsync was configured so that when a file on the server was overwritten, it copied the old one to another filename, e.g.


	/Users/daniel/letter_to_mom.indd --> backup.bonmot.ca:~daniel/bonmot/letter_to_mom.indd

And if I modified that file today, tonight:

				backup.bonmot.ca:bonmot/letter_to_mom.indd --> letter_to_mom.indd.2011-02-25T23:15
	/Users/daniel/letter_to_mom.indd --> backup.bonmot.ca:bonmot/letter_to_mom.indd

... so there would be old versions of any file that was modified available - very handy for a file type backup.

Then I had some Perl code on the disk farm that did Towers-of-Hanoi management of the versions, so it would keep a version a day old, two days, four days, eight days, 16, 32 etc.

Users could browse and retrieve their backed up files with a read-only SMB connection.

So, I set up the system - fairly simple, wrote the scripts, wrote the documentation, put a couple "Beta" sites on line, and it all worked beautifully,  so I started my market research. 

And hit a wall.  It turned out that there were two groups of Mac businesses users at the time:
* ones that already had adequate backup systems in place (mostly graphic design houses) and
* ones that could not be convinced that anyone should pay for backups and were happy to take risks.

So - that business went almost nowhere - I had a few clients for a few years.

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