As far as Bosun goes: * Self-Hosted: √. (We didn't want cloud monitoring at Stack Exchange) * Scalable: 1/2 * √. The web interface doesn't have pagination, so

As far as Bosun goes: * Self-Hosted: √. (We didn't want cloud monitoring at Stack Exchange) * Scalable: 1/2 * √. The web interface doesn't have pagination, so series with larget tagsets can cause some GUI problems. We have been having some trouble with OpenTSDB lately. People have much larger OpenTSDB installation than we do though, HBase isn't one of our best skills. But it is scaling okay for Stack Exchange * Remote Poller: √. Our agent Scollector can run in a polling mode for things that need polling like SNMP, VSphere, etc * Windows Support: √. This is one of the main reasons we built scollector. It is a single binary with no dependencies. We spend a lot of time digging into the WMI Raw performance counters to get the best data we could. * Backward Compatible with Nagios Scripts. Negative, but sc ollector can use external scripts, but they are not in the nagios format. * Thresholds: √ This is the most basic form of alerting Bosun does. You can also construct forecast, anomalous, and multiple condition alerts as well. The power in what you can do with alerting is really where Bosun shines.