Vmstat

This is a focused and fast library to get system information like:

Memory (free, active, ...)
Network Interfaces (name, in bytes, out bytes, ...)
CPU (user, system, nice, idle)
Load Average
Disk (type, disk path, free bytes, total bytes, ...)
Boot Time
Current Task (used bytes and usage time MAC OS X / Linux ONLY)

It currently supports:

FreeBSD
MacOS X
Linux (>= 2.6)
OpenBSD
NetBSD
Solaris/SmartOS

It might support (but not tested):

Older versions of linux

Installation

Add this line to your application's Gemfile:

gem 'vmstat'

And then execute:

$ bundle

Or install it yourself as:

$ gem install vmstat

Usage

Just require the library and make a snapshot or use the distinct methods to just capture parts of the statistics. For further information have a look at the rdoc.

require "vmstat"

Vmstat.snapshot # => #<Vmstat::Snapshot:0x007fe5f22df660
#	 @at=2012-10-09 21:48:57 +0200,
#	 @boot_time=2012-10-09 18:42:37 +0200,
#	 @cpus=
#	  [#<struct Vmstat::Cpu
#	    num=0,
#	    user=187167,
#	    system=144466,
#	    nice=0,
#	    idle=786622>,
#	   #<struct Vmstat::Cpu num=1, user=2819, system=1641, nice=0, idle=1113782>,
#	   #<struct Vmstat::Cpu num=2, user=158698, system=95186, nice=0, idle=864359>,
#	   #<struct Vmstat::Cpu num=3, user=2702, system=1505, nice=0, idle=1114035>,
#	   #<struct Vmstat::Cpu num=4, user=140231, system=78248, nice=0, idle=899764>,
#	   #<struct Vmstat::Cpu num=5, user=2468, system=1314, nice=0, idle=1114460>,
#	   #<struct Vmstat::Cpu num=6, user=120764, system=66284, nice=0, idle=931195>,
#	   #<struct Vmstat::Cpu num=7, user=2298, system=1207, nice=0, idle=1114737>],
#	 @disks=
#	  [#<struct Vmstat::Disk
#	    type=:hfs,
#	    origin="/dev/disk0s2",
#	    mount="/",
#	    block_size=4096,
#	    free_blocks=51470668,
#	    available_blocks=51406668,
#	    total_blocks=61069442>],
#	 @load_average=
#	  #<struct Vmstat::LoadAverage
#	   one_minute=1.74072265625,
#	   five_minutes=1.34326171875,
#	   fifteen_minutes=1.1845703125>,
#	 @memory=
#	  #<struct Vmstat::Memory
#	   pagesize=4096,
#	   wired=1037969,
#	   active=101977,
#	   inactive=484694,
#	   free=470582,
#	   pageins=102438,
#	   pageouts=0>,
#	 @network_interfaces=
#	  [#<struct Vmstat::NetworkInterface
#	    name=:lo0,
#	    in_bytes=6209398,
#	    in_errors=0,
#	    in_drops=0,
#	    out_bytes=6209398,
#	    out_errors=0,
#	    type=24>,
#	   #<struct Vmstat::NetworkInterface
#	    name=:gif0,
#	    in_bytes=0,
#	    in_errors=0,
#	    in_drops=0,
#	    out_bytes=0,
#	    out_errors=0,
#	    type=55>,
#	   #<struct Vmstat::NetworkInterface
#	    name=:stf0,
#	    in_bytes=0,
#	    in_errors=0,
#	    in_drops=0,
#	    out_bytes=0,
#	    out_errors=0,
#	    type=57>,
#	   #<struct Vmstat::NetworkInterface
#	    name=:en0,
#	    in_bytes=1321276010,
#	    in_errors=0,
#	    in_drops=0,
#	    out_bytes=410426678,
#	    out_errors=0,
#	    type=6>,
#	   #<struct Vmstat::NetworkInterface
#	    name=:p2p0,
#	    in_bytes=0,
#	    in_errors=0,
#	    in_drops=0,
#	    out_bytes=0,
#	    out_errors=0,
#	    type=6>],
#	 @task=
#	  #<struct Vmstat::Task
#	   suspend_count=0,
#	   virtual_size=2551554048,
#	   resident_size=19628032,
#	   user_time_ms=28,
#	   system_time_ms=83>>

Todo

Swap information
Support more platforms (hp ux, aix, ...)
Optimize performance for OpenBSD, NetBSD using uvmexp etc. directly
Optimize performance for solaris, smartos using kstat etc. directly
Server performance/system information (open file handles, cache sizes, number of inodes ...)