now we store a "sharded by termid" bit in posdb
key for checksums, etc keys that are not sharded
by docid. save having to do disk seeks on every
host in the cluster to do a dup check, etc.
sync when host comes back online. use udp not tcp.
host #0 can now handle a new incoming request while
a parm change is currently outstanding.
all missed "command" parms will be received when a dead host
comes back online, too, like a tight merge for instance.
does not use msg4, uses msg3e and msg3f for syncing and
sending parms.