Look at them all and make your own judgment. That way you get what suits your own style and preferences. I examined everything I could find and set up a spreadsheet with characteristics, dependencies, and so on. Took my time. Adopted mon because it suited my minimalist preferences. It has an imperceptible footprint on the server, is almost endlessly expandable with modules for monitors and alerts, and scales well. What I give up, I don't care about anyway -- things like the web GUIs, pretty pictures, and colored reports. If you have management to answer to who want those things (or if you want them), then you wouldn't pick mon.

Obviously, lots of people go for nagios. Bigger footprint on the server and more dependencies. You also get the web GUI and pretty pictures.

But there are plenty of people who also go for putting multiple pieces together and using something like cacti to integrate it.

Check 'em all out.

Been using nagios for a while with, zabbix looks even better! If you want the kind of solid, powerful config system that nagios implements with graphing integration, zabbix is the way to go. Also, its agent for remote system monitoring seems much more streamlined than NRPE. Best way to see your "real data" without hunting around for MIBs, writing tons of shell scripts, and checking that things aren't accidentally mixed up between BITps and BYTEps, etc.

Man, you must be way old school to be into mon! Nice lightweight monitoring that gives you what you need w/minimal of fuss. I use it in smaller network situations where I don't want/need complexity of OpenNMS, e.g. home office and small business networks.

hmm. Not sure if "old school" is quite the way I would want to put it.

I'm in an academic environment with a fair number of servers across a couple of departments. I just want something that will let me know when there is a problem I need to deal with. The servers are typically over worked as it is, so I want something with a light footprint (both for me and for the servers).

The biggest gripe I have is the name. If you didn't know where to find it, google would be of no use at all. If you can remember that it is kernel.org, then you can find it. But, finding independent modules is impossible if they haven't posted them at kernel.org. Same with examples and testimonials. I don't recall how I originally stumbled on it, but I was searching for quite a while trying to assemble information on all the monitoring tools available to choose from. SEC is another tool with an unfortunately unsearchable name. And Amanda's name doesn't help it much when it comes to trying to monitor blog commentary across the internet.

I say "old school" precisely because of your explanation above. Mon is from days gone by before the onslaught of "new fangled" competitors sporting feature lists of various complicated "bells and whistles". To wit, I was originally pointed to it by an old unix grey beard when I happened to be mentioning that I was working on an OpenNMS rollout... ;-P

Well, I certainly wouldn't consider myself a "unix greybeard". If anything, I might be categorized as a Macaholic. I've been into Macs since 1985 and only got into Unix around 2009.

I think the feature wars (who's got the biggest list of bells and whistles) is one of the worst things that has happened to a lot of software. Some of the best software is when someone comes along and "rethinks" the whole concept and then comes up with something that is simple, powerful, and just works. Sure, you're going to want some added capabilities, but software that just keeps piling it on ends up getting bloated and cumbersome. Better to be simple, open and extensible.

As far as keeping up with things, I am the lead on Solaris 10 systems running on the T2 (chip multi-threaded) cpu systems. I routinely work with ZFS snapshots, multi-homed SAS arrays, iSCSI, SMF, and so on. I don't really care about "new fangled" one way or the other. I just want the best choice that does what I need, whether that is something that has been around for 20 years or just came out last year.

Why no Icinga option?

Perhaps because it is a recent fork (of Nagios) and people were unaware of it? It's certainly an easy enough name to google once one is aware of it.

True, they are still basically the same behind the scenes. Although Icinga looks much nicer

My vote is for OpenNMS.

OpenNMS true Open Source with a true community.

I would to vote for Osmius but it isn't in the options

I would like to vote for Osmius too

OpenNMS. Massively customisable to monitor IP-less telecoms Equipment

Osmius has been added. While I realize it's late in the voting, this will help ensure it's there from the beginning next year.

--jeremy