CC'ed to Peter Braam for inter-mezzo comments.
On Fri, Dec 07, 2001 at 08:40:13PM +0100, Matthijs van der Klip wrote:
> Some days ago I submitted a crazy idea to sync some filesystems through
> the use of xfsdump. As I already expected this was not really a viable
> solution. Someone (Seth Mos) however pointed me to DMAPI. I have already
> done some research on it but need some info from people who know DMAPI and
> I think I can find those people on this list... :)
This sounds like a very interesting idea indeed.
> 1) Register with dmapi.
> 2) Tell dmapi I want to receive events when directory entries on a certain
> filesystem are added/deleted.
> 3) On receipt of an event append the absolute path of the modified
> directory to a logfile.
Well, you can find _one_ filename for the object that change - not
neccesarily the one the user used. For directories this would be the
same, but for files with hardlinks it may be different.
You could pretty easily extend your idea to also include getting
notified when files are written to, so the data can be synced to your
remote server. It is even possible to get a syncronious event before
data is read, so your userspace program get a chance to retrieve the
data before the read() operation completes.
To me this sounds like a really clean way to integrate something like
inter-mezzo with a standard filesystem!
--
Ragnar Kjørstad
Big Storage
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