Tino Schwarze wrote:
> An SQL approach would be rather complicated because it would have to
> support a directory structure. We would end up with ... a filesystem!
>   

Yes, but SQL databases are not the only game in town. There are other 
database architectures that would be a good choice for supporting a 
hierarchical structure, and, although I am not a Perl programmer, I am 
told by my friends who are into Perl that Perl's superior 
text-processing capabilities makes databases built solely on text files 
feasible, without requiring inclusion of or dependencies on another 
database project.

> The nice thing about using hardlinks is that the operating system keeps
> track of the link count and we can use that link count to check for
> superfluous files. This might be doable in a database as well, but
> we'd have to keep a file system and a database in sync. Doable, but
> error-prone. With the current design, there is only a file system.
>   
Yes, but there are significant tradeoffs. With the current design, you 
can't use backuppc effectively to backup a backuppc server - a 
surprising limitation for arguably the best open-source backup program. 
You can't use file systems that don't support hardlinks. You can't use 
'cloud' storage. I understand that keeping a file system and a database 
in sync opens the door for error - but there are many techniques that 
can be used to maximize database integrity at the expense of processing 
time and memory resources.

> Tino, not doing backups of the pool, but archiving hosts to tape.
>   
Yes, but my need, and I am sure, the need of many others, is to do 
remote backups. Tape works if you are local only. Additionally, tapes 
are not scaleable (you can't just run out and get a bigger tape if you 
need one - you have to change your entire tape infrastructure).

I urge the developers to consider *adding* a solution that does not 
depend on hardlinks. Such a solution could be run in parallel with using 
hardlinks and be backward-compatible.

Peter

Peter

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