Graphing Events for a pool of hosts

I am tracking a set of servers as being either up or down. Each is tagged by the region it is in and a name.
In influxdb, I would expect to write the up/down notifications (can be 1/0 or whatever makes sense), each tagged with the region and the server name and, of course, the time of the observed state change. Note that it makes sense here to write the state changes, not a continuous update of the state. Consequently I might have data in influxdb that looks like this:

I would like to chart the NET number of servers that are up and/or down over time in a region. This means for the above dataset, for the us-west region, I would expect to see 1 in the up category from 2017-01-01T17:00:00 through until 2017-01-02T17:00:00 when it would show 2, then drop down to 1 again at 2017-01-05T01:00:00 and stay there moving forwards.

I’m hoping this forum might have a solution - after considerable experimentation with dashboard options I am at a bit of a loss as to whether this is feasible. :frowning:

Not sure how to to do this in InfluxDB. Check influxdb query documentation for examples that could help

To be clear… There is no particular reason I need to track this information in influxdb. If there is an alternative data source that I could be writing this information to that would make it easier to create the dashboard I’m looking for… I’m all ears.