This manual page explains the
program. You can use
to access the NWS measurements and forecasts (see
for few examples).
This program extracts measurement data that had been generated by a
instance and then stored by a
istance. We suggest that to take full advantage of NWS, you should start a
and multiple sensors.
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.
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
the destination host (meaningful only for multi-host measurements as
latency and bandwidth)
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
if the series has been discovered thorugh the nameserver (that is using
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).
as the NWS nameserver to contact to discover if and where the data are
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
continuosly display informations. The new informations are displaied as
soon as the sensors register them. You need to ctrl-C to stop the
Specifies the frequency of the header.
lines of output (by default 20 lines).
display data starting from
instead of from the most recent going back how many line you asked for
(by default 20 lines).
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).
specifies which kind of measurements you want.
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
with a filter like '&(objectclass=nwsActivity)(name=host*)' where
is the host you are interested in.
this is to be used in conjunction with the -N options. It specifies a
filter (as defined in
) to be added in the search of the right series: usefull if you have
multiple series amongs the hosts.
has to be between (). Hint you may need to quote the filter to prevent
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
can be of the form hostname:port in case the sensors are running on non
Let's assume there is
running on machine A and that there are 2
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
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