Re: silent semantic changes with reiser4

Spam
2004-08-28T00:17:12Z

> Spam wrote:
>> > The problem is more fundamental than that. Some of the
>> > file streams proposed need to be backed up, while others
>> > are alternative presentations of the file, which should
>> > not be backed up.
>>
>> No, not really. This is a user decision and should be options in the
>> backup software. I don't think it is up to the kernel, filesystem,
>> or the OS in general to decide what information the user want to
>> retain or not.

> 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.

> 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.

I do not agree. Everything can be considered information, even if it
is derived from an already existing file.

If the user wants to not backup certain things then that is an
option to tell the backup program.

>> > Currently I see no way to distinguish between the stuff
>> > that should be backed up and the stuff that shouldn't.
>>
>> > That problem needs to be resolved before we can even start
>> > thinking about fixing archivers...
>>
>> The archivers should, as I said, allow the user to choose. It
>> shouldn't be automatic. Default, should IMO be to store everything.

> Don't try to store different views of the same thing.
> When you try to restore, you _won't_ necessarily get back what you stored.

No, it would be restored as it were before with the meta information
intact.

> Whereas if you follow the OS's advice, and skip virtual files, then
> backup and restore will recreate the filesystem, which is what you want.

> _That's_ storing everything. It's what you want from a backup.

It would be storing everything but the virtual files.

> -- Jamie