Subject: RE: Disappearing files..... clarification
From: andrew morgan (morgan@orst.edu)
Date: Fri Dec 08 2000 - 12:37:57 EST
On Fri, 8 Dec 2000, Jonathan Newman wrote:
> Roland Schulz wrote:
>
> > to the problem I described earlier. The two issues here are:
> >
> > 1) Hash collisions between different entities resulting in
> > two objects having
> > the same ID
> >
> > 2) Reuse of an ID when the old ID is created
> >
> > The Appleshare documentation is quite firm about the
> > properties the IDs
> > generated when creating new entities should have:
> >
> > a) A ID is unique. Two entities with the same ID are the
> > same entity and
> > vice versa.
> >
> > b) An ID is never reused unless it is a last resort and
> > then the oldest
> > available unused ID is to be chosen.
>
> ... snip ...
>
>
> > If not, then we should find a scheme where a) and b) both
> > hold (trivial)
> > and implement a database mapping ID to filesystem name (I think asun
> > was working in this direction, but I don't know how far it got).
> > Any volunteers?:)))
>
> The lastdid solution address (a) and for a given run of afpd also
> holds true for (b). If the lastdid solution was persistent, it would
> satisfy (b) completely.
>
> The "lastdid" solution merely keeps track of how many entries in the
> database were created and numbers them sequentially. Unfortunately,
> if I am reading the code correctly, the current database is generated
> per instance of afpd -- one per login. My concern is the
> syncronization of this database between multiple afpd instances. It
> adds a new dimension of complexity to the problem.
Really the DID should be a database stored on the filesystem somewhere, so
that not only are DIDs the same across all afpd instances, but between
reboots as well. New versions of samba will use 'tdb' (tiny-db) as their
database for storing user information, etc. This is something the samba
team has written. The advantages are that it is very lightweight because
it only has basic database features.
Andy
This archive was generated by hypermail 2b28 : Wed Jan 17 2001 - 14:32:45 EST