     migrate_recent: (opts) =>
         opts = defaults opts,
             number    : 15000
-            limit     : 4         # number to do at once in parallel
+            limit     : 10           # number to do at once in parallel
             query_limit : undefined  # how many projects to get from db -- if given basically randomly restricts to a subset
             timeout   : 1000*60*60   # 1 hour
             cb        : required

                    cb      : (err, resp) =>
                        if err
                            dbg("error calling compute server -- #{err}")
                            opts.cb(err)
                        else
                            dbg("got response #{misc.to_safe_str(resp)}")

                        i += 1
                    w = v.slice(0,i)
                    opts.cb(undefined, misc.random_choice(w).host)

    remove_from_cache: (opts) =>
        opts = defaults opts,
            host : required
        if @_socket_cache?
            delete @_socket_cache[opts.host]

    # get a socket connection to a particular compute server
    socket: (opts) =>
