111 lines
4.4 KiB
Plaintext
Executable File
111 lines
4.4 KiB
Plaintext
Executable File
<!doctype linuxdoc system>
|
|
|
|
<article>
|
|
|
|
<title>NSTAT, IFSTAT and RTACCT Utilities
|
|
<author>Alexey Kuznetsov, <tt/kuznet@ms2.inr.ac.ru/
|
|
<date>some_negative_number, 20 Sep 2001
|
|
<abstract>
|
|
<tt/nstat/, <tt/ifstat/ and <tt/rtacct/ are simple tools helping
|
|
to monitor kernel snmp counters and network interface statistics.
|
|
</abstract>
|
|
|
|
<p> These utilities are very similar, so that I describe
|
|
them simultaneously, using name <tt/Xstat/ in the places which apply
|
|
to all of them.
|
|
|
|
<p>The format of the command is:
|
|
|
|
<tscreen><verb>
|
|
Xstat [ OPTIONS ] [ PATTERN [ PATTERN ... ] ]
|
|
</verb></tscreen>
|
|
|
|
<p>
|
|
<tt/PATTERN/ is shell style pattern, selecting identifier
|
|
of SNMP variables or interfaces to show. Variable is displayed
|
|
if one of patterns matches its name. If no patterns are given,
|
|
<tt/Xstat/ assumes that user wants to see all the variables.
|
|
|
|
<p> <tt/OPTIONS/ is list of single letter options, using common unix
|
|
conventions.
|
|
|
|
<itemize>
|
|
<item><tt/-h/ - show help page
|
|
<item><tt/-?/ - the same, of course
|
|
<item><tt/-v/, <tt/-V/ - print version of <tt/Xstat/ and exit
|
|
<item><tt/-z/ - dump zero counters too. By default they are not shown.
|
|
<item><tt/-a/ - dump absolute values of counters. By default <tt/Xstat/
|
|
calculates increments since the previous use.
|
|
<item><tt/-s/ - do not update history, so that the next time you will
|
|
see counters including values accumulated to the moment
|
|
of this measurement too.
|
|
<item><tt/-n/ - do not display anything, only update history.
|
|
<item><tt/-r/ - reset history.
|
|
<item><tt/-d INTERVAL/ - <tt/Xstat/ is run in daemon mode collecting
|
|
statistics. <tt/INTERVAL/ is interval between measurements
|
|
in seconds.
|
|
<item><tt/-t INTERVAL/ - time interval to average rates. Default value
|
|
is 60 seconds.
|
|
<item><tt/-e/ - display extended information about errors (<tt/ifstat/ only).
|
|
</itemize>
|
|
|
|
<p>
|
|
History is just dump saved in file <tt>/tmp/.Xstat.uUID</tt>
|
|
or in file given by environment variables <tt/NSTAT_HISTORY/,
|
|
<tt/IFSTAT_HISTORY/ and <tt/RTACCT_HISTORY/.
|
|
Each time when you use <tt/Xstat/ values there are updated.
|
|
If you use patterns, only the values which you _really_ see
|
|
are updated. If you want to skip an unintersting period,
|
|
use option <tt/-n/, or just output to <tt>/dev/null</tt>.
|
|
|
|
<p>
|
|
<tt/Xstat/ understands when history is invalidated by system reboot
|
|
or source of information switched between different instances
|
|
of daemonic <tt/Xstat/ and kernel SNMP tables and does not
|
|
use invalid history.
|
|
|
|
<p> Beware, <tt/Xstat/ will not produce sane output,
|
|
when many processes use it simultaneously. If several processes
|
|
under single user need this utility they should use environment
|
|
variables to put their history in safe places
|
|
or to use it with options <tt/-a -s/.
|
|
|
|
<p>
|
|
Well, that's all. The utility is very simple, but nevertheless
|
|
very handy.
|
|
|
|
<p> <bf/Output of XSTAT/
|
|
<p> The first line of output is <tt/#/ followed by identifier
|
|
of source of information, it may be word <tt/kernel/, when <tt/Xstat/
|
|
gets information from kernel or some dotted decimal number followed
|
|
by parameters, when it obtains information from running <tt/Xstat/ daemon.
|
|
|
|
<p>In the case of <tt/nstat/ the rest of output consists of three columns:
|
|
SNMP MIB identifier,
|
|
its value (or increment since previous measurement) and average
|
|
rate of increase of the counter per second. <tt/ifstat/ outputs
|
|
interface name followed by pairs of counter and rate of its change.
|
|
|
|
<p> <bf/Daemonic Xstat/
|
|
<p> <tt/Xstat/ may be started as daemon by any user. This makes sense
|
|
to avoid wrapped counters and to obtain reasonable long counters
|
|
for large time. Also <tt/Xstat/ daemon calculates average rates.
|
|
For the first goal sampling interval (option <tt/-d/) may be large enough,
|
|
f.e. for gigabit rates byte counters overflow not more frequently than
|
|
each 40 seconds and you may select interval of 20 seconds.
|
|
From the other hand, when <tt/Xstat/ is used for estimating rates
|
|
interval should be less than averaging period (option <tt/-t/), otherwise
|
|
estimation loses in quality.
|
|
|
|
Client <tt/Xstat/, before trying to get information from the kernel,
|
|
contacts daemon started by this user, then it tries system wide
|
|
daemon, which is supposed to be started by superuser. And only if
|
|
none of them replied it gets information from kernel.
|
|
|
|
<p> <bf/Environment/
|
|
<p> <tt/NSTAT_HISTORY/ - name of history file for <tt/nstat/.
|
|
<p> <tt/IFSTAT_HISTORY/ - name of history file for <tt/ifstat/.
|
|
<p> <tt/RTACCT_HISTORY/ - name of history file for <tt/rtacct/.
|
|
|
|
</article>
|