Re: [SPAM] Re: silent semantic changes with reiser4

Hendrik Visage
2004-08-27T17:59:40Z

On Fri, Aug 27, 2004 at 04:41:56PM +0100, Jamie Lokier wrote:
>
> It is helpful for the OS, or a naming convention, to indicate what
> _is information_ though.
>
> It makes no sense to backup two or more copies of the _same
> information_, and it makes even less sense to try to restore them as
> it'll either be slow, fail (you can't always write to alternative
> presentations), or cause unwanted side effects.

You sure you don't mean what is data (on disk) and what is information, ie.
interpretted data?

Following this whole threat is quite interesting, but I think there are
two things that need to be pointed out (which I might've missed) is that
hardlinks would be backed up multiple times if the archiver doesn't know
the semantics of the filesystem. This is the reason why the <fs-of-choice>dump
usually are faster than tar/cpio/etc. as they understand the low level and
can optimize at that level.

Also, a user might only have access to a certain subset of information,
which he might to backup but not the rest of the stream/data, and such the
choice should be the user's.

> Just like when you backup a dynamic web site. You store the files
> which the server is using. You don't use "wget" to store the
> generated pages, that's not a useful backup and you can't restore from it.

That depends ;^)
But in the general case it's true.