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.
OPTIONS
-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)
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.
EXAMPLES
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