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sysstat's iostat wrapper for monitoring i/o usage on a unix machine with iostat installed (package sysstat)


Wrapper around iostat for Node, providing an EventEmitter to get information.

Takes (for now) an Array of iostat arguments as an array (by default ["-x"]) e.g : iostat(['-x','-m','2']);

Data comes back as an event 'data', which provides any error as a first argument (FIXME: at the moment, null), and the data as a second.

The data argument is an Object of this kind of form : { cpu: { '%user': 1.9, '%nice': 0.04, '%system': 1.12, '%iowait': 0.6, '%steal': 0, '%idle': 96.35 }, devices: { sda: { 'rrqm/s': 4.25, 'wrqm/s': 9.09, 'r/s': 0.78, 'w/s': 0.73, 'rMB/s': NaN, 'wMB/s': NaN, 'rsec/s': 160.74, 'wsec/s': 93.84, 'avgrq-sz': 56.44, 'avgqu-sz': 0.25, await: 54.94, svctm: 5.64, '%util': 2.55 } } }

This library has essentially been made in order to run in continuous mode, with options like ["-x","-m","2"].


var iostat = require('iostat');
iostat().on('data', function(err, stats) {
    console.log(stats.devices.sda1["%util"]); //e.g. 0.91 (as a Number, not a String)

Continuous mode example

var iostat = require('iostat');
iostat(['-x','-m','2']).on('data', function(err, stats) {
    if (stats.devices.sda && stats.devices.sda["%util"] > 1)
        throw "Your system is suffering! consider sharding you data!";


This is an early release, but it's yet mostly usable. Expect maybe some issue like getting sometime NaN rather than the number you expect;