On 10/6/06, Matthew Ahrens <[EMAIL PROTECTED]> wrote:
Jeremy Teo wrote:
> A couple of use cases I was considering off hand:
>
> 1. Oops i truncated my file
> 2. Oops i saved over my file
> 3. Oops an app corrupted my file.
> 4. Oops i rm -rf the wrong directory.
> All of which can be solved by periodic snapshots, but versioning gives
> us immediacy.
>
> So is immediacy worth it to you folks? I rather not embark on writing
> and finishing code on something no one wants besides me.
In my opinion, the marginal benefit of per-write(2) versions over
snapshots (which can be per-transaction, ie. every ~5 seconds) does not
outweigh the complexity of implementation and use/administration.
It may quite possibly not be worth adding the second, fairly similar,
facility. In addition to the points you cite, trying to explain to
average users what the two are and when to use each one would be
fairly challenging.
All the arguments about piles of version seem to apply in spades to
taking snapshots every 5 seconds. And given the snapshot hierarchy,
it's much harder to find your file in the snapshot you want (let's say
your file is 5 or 10 directories down, quite common in source trees in
my experience; you have to go back to the top and navigate to
~/.zfs/<weirdsnapshotdirectoryname>/foo/bar/mumble/bag/baz/etc/the-file-I-want.cpp
in each snapshot that might have the version you're looking for.
I'd say the snapshot system is not as good as file versioning for the
tasks I think file versioning is best for. However, snapshotting at
very freaquent intervals would definitely capture close enough to the
version I need to retrieve to make it a tolerable alternative. The
user interface to it for retrieving a file is rather harder to use, it
seems to me, and that might possibly discourage use when it would have
been helpful.
--
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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