[tahoe-dev] web "control panel", static server selection UI

Greg Troxel gdt at ir.bbn.com
Mon Jan 24 21:23:18 UTC 2011

Sorry to be a wet blanket, but: I see why you propose this, but I worry
that it will be too inflexible.

A key property is that  with some churn things still work.  Once you
add 'required', that breaks.

For 'allowed', I would want to phrase it as "disable use of this server"
because the default in a grid is to use all.   It's not clear what the
motivation for disabling is - performance, cost, or reliability.

I wonder about a priority # per server, to bias the selection rather
than being absolute.

Required is too binary.  I think 'shares.independent', what
servers-of-happiness should be renamed to :-), has a clear meaning:
ensure that at least I independent servers have at least 1 share.  But
the real thing to express is much more complicated, and is really about
correlated failure modes.  If I check required, then I have no
resilience to a server being unreachable once in a while.  If I had 6
servers and each were there 99% of the time I might not care which 5 of
the 6 got shares.

Plus, there's load balancing by free space.

This should all be tied in to repair and rebalancing, so that one can
hill climb on preferences.
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