Re: [9fans] Sources Gone?

["Roman V. Shaposhnik" <rvs@sun.com>]

On Thu, 2009-01-29 at 16:42 -0500, erik quanstrom wrote:
> > That said, what would be your thoughts on developing the
> > tools (and interfaces perhaps) for fetching up venti
> > blocks between two systems in a secure and manageable way.
>
> i think this harks back to ye olde dump.  the main difference
> is that "inode number" has now become a "score" and gotten
> much fatter.
>
> the problem at this level is it's hard to maintain any differences.
> (you can't skip one of a sequence of 6 incremental dumps.)

To use git as an example here, it has a concept of a shallow clone,
where it lets you skip the history older than a particular date.

> or apply changes from one venti to another.

What do you mean by "apply changes"? Each venti has a set of
blocks corresponding to vac hierarchies. Each vac hierarchy
has a single parent. Retrieving the missing blocks reachable
from a hierarchy of interest to you is all that is needed.

> i don't see how to make sense of venti-level syncing unless it is so
> basic that you dump all the blocks from one venti into another.
> in which case, no special tools are needed.

Some level of smartness in how block traversal is made needs to
be there. I would also like to have an agent close to the actual
server hosting venti archive being able to do things on my behalf
and only sending the results back (e.g. traversing the hierarchies
only to determine that certain things are not needed is painful
over the network). Plus there has to be a security mechanism that
would not allow me to request random blocks, unless I'm authorized.

Thanks,
Roman.