[tahoe-dev] Question about changing k/N

[Kyle Markley]

Hi developers,

I'd like to know what I should expect if I change my k / N values on an 
operating grid.  Of course, this is a question I should have asked ahead 
of time, but didn't, and I'm actually asking because I'm getting an 
error.  :)

Formerly, I used shares.needed=2 and shares.total=4.
Lately, I changed to shares.needed=4 and shares.total=10.

I've observed that tahoe is a little unhappy about updating mutable 
files that use the old 2/4 encoding.  For example a "tahoe ln" operation 
to link a 4/10 directory into a 2/4 directory succeeds, but then also 
throws an UncoordinatedWriteError.  I also had trouble with "tahoe 
backup" writing to a 2/4 directory - it gave me an error at the end, 
although the new backup appeared in the Archives directory.

Am I operating in a perilous and not-well-supported area?  I would argue 
that to support the multiple-user file-sharing use model, this ought to 
work well, because different users may use different encoding parameters 
on the same grid but ought to have clean interoperability.

-- 
Kyle Markley