On Thu, Nov 21, 2013, at 0:23, Jeremy Laidman wrote:
Good Xymon Folks
Xymon doesn't support reporting "actual" memory usage for FreeBSD systems
Correct, and this is quite annoying!
- I could report each of the different memory metrics separately to Xymon: active, inactive, wired, cache, buffers, free. Then I can graph them all, and look for various conditions on each of them separately, or in certain combinations that make sense. This is the most flexible option, and would provide the highest degree of insight to someone trying to troubleshoot a sluggish server, but it requires a lot more work on both client and server. It's also specific to *BSD systems.
Yes, more data is better. For example, look at what Observium pulls over SNMP vs what Xymon reports:
So, any other suggestions on the best way to achieve this? Which of the above is the best approach, do you think?
The other issue I have is that nobody seems to agree on what's a useful measure to keep an eye on. The Xymon server-side code for Darwin reports used memory as the sum of active, inactive and wired. But other sources use the sum of active, wired, cache and buffers. Yet other sources say that buffers cannot be freed, and also that inactive pages are kind-of available if needed. My intention is to be able to predict when it's time to add RAM to avoid performance degradation, but it's not clear what numbers are going to give me that.
Graph it all as granularly as you can. Let the admins figure out what's important to monitor.