[Xymon] iostat for Linux

[John Horne]

On Tue, 2012-08-07 at 09:52 +0800, Colin Coe wrote:
> Hi all
> 
> Google knows a lot about $SUBJECT but unfortunately, a lot of the info
> is conflicting.
> 
> What's the current wisdom for collecting and graphing iostat info on
> Linux?  Specifically, I'm using RHEL5 and RHEL6.
> 
Hi,

I recently asked about monitoring iostat myself - see the thread here
http://lists.xymon.com/pipermail/xymon/2012-August/035229.html

One reply mentions some scripts on xymonton. I also received a private
reply that there were some scripts on Sourceforge - search for 'Linux
iostat'.

I ended up writing a reasonably short script myself which runs on the
clients. It records the 'avtime', 'svctime' and the percent 'busy'
values. I produce two graphs - one for the percent busy, the other shows
both time values. Both graphs appear in 'trends', and the 'busy' graph
appears on an 'iostats' test status page. (Note, because Xymon already
sort of knows about an 'iostat' test I could not use that name, so used
'iostats' instead.) The script sends a 'status' report (using 'xymon
<server> "status ...") for the 'iostats' test. If the percent busy is
high it sends a yellow status, if it is very high then a red status is
sent. Additionally, a 'data' report (using 'xymon <server> "data ...")
containing the time and busy values is sent back to the Xymon server. On
the server I run a script which is used by 'xymon_rrd' (via the
'--extra-script' and '--extra-tests' options; see the man page and look
in tasks.cfg). The script tells Xymon what RRD files to create and what
the DS entries and values are, from the data received from the client.
(Sorry, that may all sound horrendously complicated. However, it works
very well, and once set up is very easy to maintain. I currently run
three tests like this.)

I would say that monitoring iostat has proved to be useful to us. It is
not something we monitored with Big Brother, but has already shown that
we have two servers which regularly show very high disk I/O. No idea why
yet.





John.

-- 
John Horne, Plymouth University, UK
Tel: +44 (0)1752 587287    Fax: +44 (0)1752 587001