[tahoe-dev] servers-of-happiness default of 7 prevents first-time installation from working "out of the box"

[Brian Warner]

> At 2010-06-15 17:14 (-0600), Zooko O'Whielacronx wrote:
> 
>> One possible solution to this would be to lower the default
>> servers-of-happiness from 7 to 1. This would require us to also lower
>> the default number of shares needed from 3 to 1, because the current
>> code won't let you have a servers-of-happiness lower than your
>> number-of-shares-needed:

That's disappointing. I haven't looked closely at the
shares-of-happiness changes, but I was hoping that it merely added a
post-server-selection assertion that the shares were sufficiently
distributed.

I'd love it if we could lower the default SOH to 1 and leave the default
k=3/N=10. People who have just one server will see everything work
properly (and even get better reliability than if k=1/N=1 or k=1/N=3,
since they can tolerate single-sector errors or bitflips that kill one
share but not the others). People who have multiple servers will get
improved protection against whole-drive failures. And people who have
multiple servers and want to avoid accidentally uploading files (to just
themselves) when they're really offline can raise SOH to prevent that.

I'd suggest removing the "SOH>=k" assertion and setting SOH=1 by default.

cheers,
 -Brian