1 <!doctype linuxdoc system> 2 3 <article> 4 5 <title>NSTAT, IFSTAT and RTACCT Utilities 6 <author>Alexey Kuznetsov, <tt/kuznet@ms2.inr.ac.ru/ 7 <date>some_negative_number, 20 Sep 2001 8 <abstract> 9 <tt/nstat/, <tt/ifstat/ and <tt/rtacct/ are simple tools helping 10 to monitor kernel snmp counters and network interface statistics. 11 </abstract> 12 13 <p> These utilities are very similar, so that I describe 14 them simultaneously, using name <tt/Xstat/ in the places which apply 15 to all of them. 16 17 <p>The format of the command is: 18 19 <tscreen><verb> 20 Xstat [ OPTIONS ] [ PATTERN [ PATTERN ... ] ] 21 </verb></tscreen> 22 23 <p> 24 <tt/PATTERN/ is shell style pattern, selecting identifier 25 of SNMP variables or interfaces to show. Variable is displayed 26 if one of patterns matches its name. If no patterns are given, 27 <tt/Xstat/ assumes that user wants to see all the variables. 28 29 <p> <tt/OPTIONS/ is list of single letter options, using common unix 30 conventions. 31 32 <itemize> 33 <item><tt/-h/ - show help page 34 <item><tt/-?/ - the same, of course 35 <item><tt/-v/, <tt/-V/ - print version of <tt/Xstat/ and exit 36 <item><tt/-z/ - dump zero counters too. By default they are not shown. 37 <item><tt/-a/ - dump absolute values of counters. By default <tt/Xstat/ 38 calculates increments since the previous use. 39 <item><tt/-s/ - do not update history, so that the next time you will 40 see counters including values accumulated to the moment 41 of this measurement too. 42 <item><tt/-n/ - do not display anything, only update history. 43 <item><tt/-r/ - reset history. 44 <item><tt/-d INTERVAL/ - <tt/Xstat/ is run in daemon mode collecting 45 statistics. <tt/INTERVAL/ is interval between measurements 46 in seconds. 47 <item><tt/-t INTERVAL/ - time interval to average rates. Default value 48 is 60 seconds. 49 <item><tt/-e/ - display extended information about errors (<tt/ifstat/ only). 50 </itemize> 51 52 <p> 53 History is just dump saved in file <tt>/tmp/.Xstat.uUID</tt> 54 or in file given by environment variables <tt/NSTAT_HISTORY/, 55 <tt/IFSTAT_HISTORY/ and <tt/RTACCT_HISTORY/. 56 Each time when you use <tt/Xstat/ values there are updated. 57 If you use patterns, only the values which you _really_ see 58 are updated. If you want to skip an unintersting period, 59 use option <tt/-n/, or just output to <tt>/dev/null</tt>. 60 61 <p> 62 <tt/Xstat/ understands when history is invalidated by system reboot 63 or source of information switched between different instances 64 of daemonic <tt/Xstat/ and kernel SNMP tables and does not 65 use invalid history. 66 67 <p> Beware, <tt/Xstat/ will not produce sane output, 68 when many processes use it simultaneously. If several processes 69 under single user need this utility they should use environment 70 variables to put their history in safe places 71 or to use it with options <tt/-a -s/. 72 73 <p> 74 Well, that's all. The utility is very simple, but nevertheless 75 very handy. 76 77 <p> <bf/Output of XSTAT/ 78 <p> The first line of output is <tt/#/ followed by identifier 79 of source of information, it may be word <tt/kernel/, when <tt/Xstat/ 80 gets information from kernel or some dotted decimal number followed 81 by parameters, when it obtains information from running <tt/Xstat/ daemon. 82 83 <p>In the case of <tt/nstat/ the rest of output consists of three columns: 84 SNMP MIB identifier, 85 its value (or increment since previous measurement) and average 86 rate of increase of the counter per second. <tt/ifstat/ outputs 87 interface name followed by pairs of counter and rate of its change. 88 89 <p> <bf/Daemonic Xstat/ 90 <p> <tt/Xstat/ may be started as daemon by any user. This makes sense 91 to avoid wrapped counters and to obtain reasonable long counters 92 for large time. Also <tt/Xstat/ daemon calculates average rates. 93 For the first goal sampling interval (option <tt/-d/) may be large enough, 94 f.e. for gigabit rates byte counters overflow not more frequently than 95 each 40 seconds and you may select interval of 20 seconds. 96 From the other hand, when <tt/Xstat/ is used for estimating rates 97 interval should be less than averaging period (option <tt/-t/), otherwise 98 estimation loses in quality. 99 100 Client <tt/Xstat/, before trying to get information from the kernel, 101 contacts daemon started by this user, then it tries system wide 102 daemon, which is supposed to be started by superuser. And only if 103 none of them replied it gets information from kernel. 104 105 <p> <bf/Environment/ 106 <p> <tt/NSTAT_HISTORY/ - name of history file for <tt/nstat/. 107 <p> <tt/IFSTAT_HISTORY/ - name of history file for <tt/ifstat/. 108 <p> <tt/RTACCT_HISTORY/ - name of history file for <tt/rtacct/. 109 110 </article> 111
