If you're looking at scaling monitoring timeseries data you may also wanter to consider more Availability leaning architecture (in the CAP theory sense) with respect to replication (i.e. quorum write/read replication, strictly not leader/follower - active/passive architecture) then you might also want to check out the Apache 2 project M3 and M3DB at m3db.io.
I am biased obviously as a contributor. Having said that I think it's always worth understanding active/passive type replication and the implications and see how other solutions handle this scaling and reliability problem to better understand the underlying challenges that will be faced with instance upgrades, failover and failures in a cluster.
Neat! Hadn't heard of M3DB before, but cursory poke around the docs seems like it's a pretty solid solution/approach.
My current use case isn't monitoring, or even time series anymore, but will keep M3DB in mind next time I have to seriously push a time series/monitoring solution.
I am biased obviously as a contributor. Having said that I think it's always worth understanding active/passive type replication and the implications and see how other solutions handle this scaling and reliability problem to better understand the underlying challenges that will be faced with instance upgrades, failover and failures in a cluster.