nws_extract - extracts measurements and forecast from the Network Weather Service

nws_extract [-aS][-f fieldList][-h n][-M host][-n n][-N host][-t n][-w] resource [filter] host [host ...]

This manual page explains the nws_extract program. You can use nws_extract to access the NWS measurements and forecasts (see EXAMPLES for few examples).

This program extracts measurement data that had been generated by a nws_sensor(1) instance and then stored by a nws_memory(1) istance. We suggest that to take full advantage of NWS, you should start a nws_nameserver(1) and multiple sensors.

-a Treat all listed machines as experiment sources. By default, the program treats the first machine as the experiment source and the others as experiment destinations. Use this switch to get information about all pairs of machines.

-f fieldlist Specifies which information you would like displayed. fieldList is a comma-delimited list of forecast field names that you would like to see. The recognized names are

destination the destination host (meaningful only for multi-host measurements as latency and bandwidth)

source the source host

resource the name of the resource measured

measurement the values measured by the nws_sensor(1)

time the time at which the measurement is taken (as measured by the nws_sensor(1)

mae_error, mae_forecast, mse_error, mse_forecast, mse_method these are the various forecasts, the computed errors and the method used in the computation (where mae is mean absolute error and mse is mean squared error).

option if the series has been discovered thorugh the nameserver (that is using the -N option) you can use this fields to print the options used to start the activity responsible for this series (useful if you have series that differ only for the options).

-N host use host as the NWS nameserver to contact to discover if and where the data are available.

-M host use host as the NWS memory to contact to retrieve the NWS measurements. When this options is set, no NWS nameserver is contacted (that is -N is discarded if specified).

-w continuosly display informations. The new informations are displaied as soon as the sensors register them. You need to ctrl-C to stop the program.

-h n Specifies the frequency of the header.

-n howmany display howmany lines of output (by default 20 lines).

-t time display data starting from time instead of from the most recent going back how many line you asked for (by default 20 lines).

-S there is no resource/filter/host(s) but only series name. The series are not checked against a nameserver (-N options isn't used) but a memory needs to be specified (-M required).

resource specifies which kind of measurements you want. resource is typically (but may depends on compile options) bandwidthTcp, latencyTcp, availableCPU, currentCPU (to get the list of available resources for a specific host you can use nws_search(1) with a filter like '&(objectclass=nwsActivity)(name=host*)' where host is the host you are interested in.

filter this is to be used in conjunction with the -N options. It specifies a filter (as defined in nws_search(1) ) to be added in the search of the right series: usefull if you have multiple series amongs the hosts. filter has to be between (). Hint you may need to quote the filter to prevent shell expansion.

host [host...] these are the lists of hosts for which you are interested in getting the measurements. For some resource (say latencyTcp) you need at least 2 hosts. host can be of the form hostname:port in case the sensors are running on non standard ports.

Let's assume there is nws_nameserver(1) running on machine A and that there are 2 nws_sensor(1) running on machine A and B.

nws_extract -N A avail B

will extract data for availableCPU for machine B and

nws_extract -N A avail -f time,measurement B

will do the same but prints out only the timestamps and the measurements (no forecasts).

If you have multiple cliques running between A and B, say with different experiment size (one with the default 64 the other wiht 512) you can query for all the bandwidth experiments

nws_extract -N A band A B

or for only the 512 data

nws_extract -N A band "(size=512)" A B

Bugs list is at http://nws.cs.ucsb.edu.

NWS is an original idea of Rich Wolski Rich Wolski (rich@cs.ucsb.edu) who came up with the original nws_memory.

Neil Spring, Jim Hayes (jhayes@cs.ucsd.edu) and Martin Swany maintained and enhanced it.

Graziano Obertelli (graziano@cs.ucsb.edu) currently maintains NWS and wrote this man page.

nws_sensor(1), nws_search(1), nws_nameserver(1), nws_extract(1) halt_activity(1) start_activity(1)