[Xymon] FreeBSD Actual Memory Usage

[Jeremy Laidman]

On 22 November 2013 08:49, Mark Felder <feld at feld.me> wrote:

>
> Yes, more data is better. For example, look at what Observium pulls over
> SNMP vs what Xymon reports:
>
> http://imgur.com/a/P4Qq1


Now, that's what I want!

Interestingly, Observium(SNMP) splits all memory into
used+cached+buffers+shared+free.  I don't know where those numbers come
from - they don't map neatly to what "top" shows:
active+inactive+wired+cache+buffers+free.  So used+shared =
active+inactive+wired??

According to this:
http://www.daemonforums.org/showthread.php?t=2125Net-SNMP counts cache
memory twice when calculating MIB::memAvailReal.0.
 It's a bit suspect.

> So, any other suggestions on the best way to achieve this?
>


> Graph it all as granularly as you can. Let the admins figure out what's
> important to monitor.
>

You're correct of course.  But it's the most work, and the least likely to
get completed anytime soon.

A bigger problem is that Xymon's genericised way of reporting memory is a
call to unix_memory_report() with parameters for total, used and actual -
and that's all.  (For FreeBSD and others, "actual" is set to -1.)  The
function unix_memory_report() does the memory threshold checks (via status
message) and also governs what gets sent to the RRD files.  If I wanted to
alert on all available memory numbers, and to have them all on the graph
for the "memory" page, I'd have to find another way to get them sent to the
RRD files and to check for threshold violations, because Xymon is simply
not geared up to do this.  And it probably won't ever be, because different
OSes do memory management differently.

I think what I'm left with is a two-prong approach.

1) Improve the "memory" page: I need to have "actual" memory reported by
the client, and parsed by the OS-specific code in xymond, so that it
thresholds on, and generates a status message with, 3 numbers instead of
two.  This needs adjustments to the client-side code
client/freebsd-meminfo.c, to add an "Actual: nnn" line to its output; and
also to the server-side code xymond/client/freebsd.c, to parse that line in
the same way that the Linux code does.

2) Display the extra numbers: I need to get all the separate numbers -
perhaps from [top] - reported into a completely separate graph (eg
[topmem]), that can be viewed on the trends page.  I can knock up a
server-side perl script to do that right now, but ultimately this would be
best done in the Xymon server-side code (probably xymond/client/freebsd.c),
and could include thresholding if it makes sense.

J
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.xymon.com/pipermail/xymon/attachments/20131122/940e9385/attachment.html>