On Mon, Aug 6, 2012 at 1:38 PM, Tony Arcieri <[email protected]> wrote: > On Mon, Aug 6, 2012 at 12:30 PM, Zooko Wilcox-O'Hearn <[email protected]> > wrote: >> >> How can both that story and also the things that have already been >> posted on this thread both be true?
... > As far as CAP theorem goes, it sounds like Tahoe falls into the AP space, > that is: network partitions do not (necessarily) result in a loss of > availability of service, however the two partitions may become inconsistent > during the event of a network partition. > > From what I've read of how Tahoe handles conflicts, it employs a monotonic > version number and timestamps. So it sounds like in the event of a conflict, > Tahoe employs a last writer wins strategy? You are right about your guesses here. *Except*, I don't think any of this applies to the VTLUUG story. My assumption is that never during the partition did anyone attempt to write to the same file or directory that someone on the other side of the partition also wrote to. In fact, it is quite likely that there were no files or directories to which write access was held by people on both sides of the partition! So, empirically, all this distributed consistency stuff that we're talking about is technically correct, and could probably be very useful in some specific cases, but with the Tahoe-LAFS access control architecture -- in which most things are immutable, and most mutable things are writable by few or only one writer -- such cases appear to be very rare. Regards, Zooko _______________________________________________ tahoe-dev mailing list [email protected] https://tahoe-lafs.org/cgi-bin/mailman/listinfo/tahoe-dev
