Re: kernel.bkbits.net off the air

[H. Peter Anvin]

Andrea Arcangeli wrote:
> 
> we've to start rsync three times to get them in order, 3 tcp
> connections, there's no way to specify the order in the rsync command
> line, infact those two sequence files can be as well outside the tree
> and we can fetch temporarily in a /tmp/ directory or similar. However we
> can probably hack the rsync client to be able to specify the two
> sequence numbers on the command line.
> 
> It maybe also cleaner to use a slightly more complicated but more
> compact algorithm, this would make a potential new rsync command line
> option cleaner since only 1 sequence file would need to be specified:
> 
> 	do {
> 		seq = fetch(sequence-file);
> 		if (seq & 1)
> 			break;
> 		rsync
> 		if (seq != fetch(sequence-file))
> 			seq = 1;
> 	} while (seq & 1 && sleep 10 /* ideally exponential backoff */)
> 
> this way only 1 sequence-file is needed for each repository that we want
> to checkout. the server side only has to increase twice the same file
> before and after each update of the repository, so the server side is
> even simpler (with the only additional requirement that the sequence
> number has to start "even"), only the client side is a bit more complicated.
>

Good grief.  This is messy as hell, and really interferes rather badly
with the whole kernel.org mirror setup.

I guess the "best" solution is to use LVM atomic snapshots, and only
allow rsync off the atomic snapshot.  That way any particular rsync
session would always be consistent.  That's a *HUGE* amount of work,
though, and still doesn't solve the mirrors issue -- I don't control
what the mirrors run.  On the other hand, I don't know how many mirror
sites actually mirror /pub/scm since it's not a requirement.

	-hpa

-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/