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Langue: en

Version: September 27, 2002 (debian - 07/07/09)

Section: 1 (Commandes utilisateur)


start_activity - instructs the Network Weather Service to start monitoring resources


start_activity [-F][-a][-f file] host [attribute:value ...]


This manual page explains the start_activity program. You can start to monitor resources using start_activity and you can use halt_activity(1) to stop the monitoring.

start_activity contacts a nws_sensor(1) running on host and instructs it to start the activity specified by attribute:value. Here is a list of attribute you can specify (is not complete)


specifies the unique name that specifies the activity to be started. If you don't specify one, an automatic one will be generated.


specify the resource that can be monitored (cpuMonitor, diskMonitor, memoryMonitor, tcpConnectMonitor, tcpMessageMonitor)


specify the control that is ultimately responsible for how frequently measurements are taken. periodic and clique are the allowed values: the former takes one host measurements (cpuMonitor) and the latter takes care of the multiple host measurements (tcpMessageMonitor)


specify a host that is part of this clique. Tipically you will have at least 2 of these options. You can specify members with the host:port format. Currently there is a limitation of 100 member for a clique.


specify how many seconds between measurements.


specify the size of the experiment to be conducted (valid only for 2 hosts experiments like bandwidth experiment). This is the total number of kB sent for a single experiment (default is 64 for versions 2.6 and smaller, 256 for the others).


specify the size of the messagei (measured in kB) to be used during network experiments. It cannot be bigger then what specify by size. Default is 16 kB.


specify the buffer to be requested when opening a socket to conduct a network experiment (measured in kB). Not all systems allows the user to change this value: NWS will revert to what is allowed in this case. Default is 32 kB.

You can see EXAMPLES later on for a simple example.



force the nws_sensor to start the activity even if a record still exists in the nws_nameserver


restart all activities on this host

-f file

read attribute:value from file instead of the command line.


Let's suppose we have few machines already running nws_sensor(1) and that we want these nodes to begin performing measurements (of latency and bandwidth in this example). Let A, B and C be three such hosts. You can create a configuration file that defines this situation and then execute start_activity to refer to this configuration using the -f switch. Here is a sample configuration file:

This instucts the sensors to form a clique named pippo whose members are A, B and C, that uses a message size of 32K and that takes measurements every 120 seconds. The command line will be

start_activity -f file A


Bugs list is at


NWS is an original idea of Rich Wolski Rich Wolski ( who came up with the original nws_memory.

Neil Spring, Jim Hayes ( and Martin Swany maintained and enhanced it.

Graziano Obertelli ( currently maintains NWS and wrote this man page.


nws_sensor(1), nws_search(1), nws_nameserver(1), nws_extract(1) halt_activity(1)
Une théorie est scientifique si et seulement si elle susceptible d'être
réfutée ; elle n'est pas vraie, mais tout au plus admise provisoirement.
-+- Karl Popper -+-