On 9/12/06, eric kustarz <[EMAIL PROTECTED]> wrote:

So it seems to me that having this feature per-file is really useful.
Say i have a presentation to give in Pleasanton, and the presentation
lives on my single-disk laptop - I want all the meta-data and the actual
presentation to be replicated.  We already use ditto blocks for the
meta-data.  Now we could have an extra copy of the actual data.  When i
get back from the presentation i can turn off the extra copies.

Yes, you could do that.

*I* would make a copy on a CD, which I would carry in a separate case
from the laptop.

I think my presentation is a lot safer than your presentation.

Similarly for your digital images example; I don't consider it safe
until I have two or more *independent* copies.  Two copies on a single
hard drive doesn't come even close to passing the test for me; as many
people have pointed out, those tend to fail all at once.  And I will
also point out that laptops get stolen a lot.  And of course all the
accidents involving fumble-fingers, OS bugs, and driver bugs won't be
helped by the data duplication either.  (Those will mostly be helped
by sensible use of snapshots, though, which is another argument for
ZFS on *any* disk you work on a lot.)

The more I look at it the more I think that a second copy on the same
disk doesn't protect against very much real-world risk.  Am I wrong
here?  Are partial(small) disk corruptions more common than I think?
I don't have a good statistical view of disk failures.
--
David Dyer-Bennet, <mailto:[EMAIL PROTECTED]>, <http://www.dd-b.net/dd-b/>
RKBA: <http://www.dd-b.net/carry/>
Pics: <http://www.dd-b.net/dd-b/SnapshotAlbum/>
Dragaera/Steven Brust: <http://dragaera.info/>
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