[CentOS] Re: [OT] What is the best network monitoring tool?

Les Mikesell lesmikesell at gmail.com
Mon Oct 13 23:16:24 UTC 2008

nate wrote:

> Last I checked as well the SNMP daemon didn't return cpu i/o
> wait values, which is pretty handy to have.

It must... I haven't waded through the details of how it does it, but a 
default OpenNMS install will collect and graph a CPU usage chart that 
stacks user/nice/wait/system/interrupts and seems accurate except that 
it is per-cpu (i.e. will go to 400% on a hyperthreaded dual-cpu box).

It also does a CPU statistics chart that does a line graph for the 
1/5/15 minute values with the space under the line color-coded for %cpu 

> Then I have a script that queries the data(along with other
> data) and feeds it into cacti as a single set of results
> (to be stored in 1 RRD file) which really helps cacti scale
> [cacti at dc1-mon002:~/bin]$ ./linux-basics-net.pl us-cfe002 public
> USER:0.01 NICE:0.00 SYS:0.02 IO:0.00 FAULT:61.78 TCPSOCK:21 RAM_T:3950
> RAM_F:2732 RAM_B:58 RAM_C:731 SWAP_T:8189 SWAP_U:0 DISK_T:60707 DISK_U:9567
> 1MIN:0.00 5MIN:0.00 15MIN:0.00 E0_IN:747203652 E0_OUT:520021358 E1_IN:0
> E1_OUT:0

And it does  a system memory stats graph with color-coded:
used/io_buff/shared/filesytem cache/available/swap/real values.

> Unfortunately with every passing revision of sar it becomes
> more and more difficult to parse, I really miss the version
> from RHEL 3 days, that one was great, it had a special
> human readable output option which has since been taken out
> (it would spit out each stat on one line making it easy
> to parse).

You might want to look at opennms if you haven't already.  Now that they 
have a yum repo it is very easy to install.

   Les Mikesell
    lesmikesell at gmail.com

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