I'm not sure what to think about Jody's preference for mutable files because of storage space concerns. Tahoe-LAFS v1.5 *does* have garbage collection -- it is just slow and it requires manual operation. So I'm not sure whether Jody is better or worse off by using mutable files -- in terms of storage space.
Another performance issue with mutable files -- besides the RAM usage and the download time earlier mentioned in this thread -- is that each new mutable file requires its own RSA public/private key-pair, which takes a lot of CPU cycles to generate. Really a lot! Like a billion CPU cycles. That's enough to actually inconvenience you if you make new ones frequently enough, even if you have a modern super-powered CPU running at 3 GHz. (Future versions of the Tahoe-LAFS crypto cap format will use a more efficient public key signature algorithm like ECDSA so that you can create lots of mutable files without wasting lots of CPU cycles.) I guess these performance issues with mutable files need to be added to the documentation in some appropriate place. Could someone else please do that job? I'm not sure off the top of my head where such a warning would serve its purpose. Please submit a patch, even if it is just the output of "diff", attached to a ticket. Here: I created #878. Thanks! Zooko http://allmydata.org/trac/tahoe/ticket/878# warn users about the performance issues of mutable files _______________________________________________ tahoe-dev mailing list [email protected] http://allmydata.org/cgi-bin/mailman/listinfo/tahoe-dev
