[tahoe-dev] plans for tahoe-1.3.1

[Andrej Falout]

Much appreciated, Zooko.

I just reported to Allmydata.com support a significant slowdowns I am
experiencing when backing up over longer periods of time (10-15 hours). I
wanted to make sure that was not a network issue before reporting it on this
list.

> In fact, that graph reminds me of an even *easier* hack, just set the
> segment size back to a few MiB instead of its currently value of 128
> KiB, and see if that significantly improves performance from Andrej's
> perspective!

Please let me know when there is something to test.

Also, I'm not clear on what 'tahoe backup' does when only a small part of
the file changes - does it upload only changed blocks, or the whole file?
I'm sure this is documented somewhere, but unfortunately I am not fammiliar
with the terminology used in many places.

What happens to the files that are moved/renamed?

Cheers,
Andrej


On Tue, Mar 10, 2009 at 4:04 AM, zooko <zooko at zooko.com> wrote:

> On Mar 4, 2009, at 20:23 PM, Andrej Falout wrote:
>
> > In your plans, is there something you can do to improve upload
> > speed? Directory creation speed?
>
> Thanks for the feedback!  Again, I'm really glad to have an end-user
> on this list reminding the developers of what he wants.
>
> Let's prioritize faster uploads and downloads for tahoe-1.4.  This is
> the ticket describing what we already know about it:
>
> http://allmydata.org/trac/tahoe/ticket/392 # pipeline upload segments
> to make upload faster
>
> It would actually be a reasonable task for a newcomer to tackle.  To
> real solve it in the best possible way is equivalent to
> reimplementing TCP on top of foolscap messages, or else switching
> from foolscap to HTTP for storage protocol, but to do some reasonable
> hack that makes it, let's say "twice as fast", for typical
> situations, should be quite doable.
>
> See these graphs of how throughput has *dropped* dramatically as
> we've changed Tahoe to make it better along other dimensions:
>
> http://allmydata.org/tahoe-figleaf-graph/hanford.allmydata.com-
> tahoe_speedstats_rate.html
>
> In fact, that graph reminds me of an even *easier* hack, just set the
> segment size back to a few MiB instead of its currently value of 128
> KiB, and see if that significantly improves performance from Andrej's
> perspective!
>
> Regards,
>
> Zooko
> - Show quoted text -
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> tahoe-dev at allmydata.org
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>



-- 
Andrej Falout
AU: +61 (410) 463 735 NZ: +64 (21) 0256 6825 US: +1 (360) 488 0970
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