scoreboard server status

[gdt]

Currently, much information is potentially available to a node about the behavior of peers. Every DYHB and share put/fetch tells us something, but this doesn't seem to be stored in an organized way for display/management, and it doesn't seem to be used to deal with a failing server.

This ticket asks for per-server state to be stored about latency and success/failure of various operations, and for it to be displayable in the WUI, perhaps by making each server line a link to a per-server detailed page, and by having a green/yellow/red coloring of each server.

Besides errors, an important item to scoreboard is the server's willingness to take shares. One often sees 12 servers available in the pubgrid, yet 3/7/10 encodings have been unworkable for weeks. Taking shares might be expressible in terms of the range known to work and not work, and probably this should be expressed in advertisements and then scoreboarding can be about failure to honor the advertisement.