@nk20  I am confused by your concern about in memory state.  Can you provide more detail around what you are being told or what you have read that has lead to this concern?  Perhaps those concerns are about something more than component state? Perhaps I can address those specific concerns. Not all NiFi components retain state.  Those that do either persist that state to disk in a local state directory or write that state to zookeeper. As long as that local disk where state directory is persisted is not lost and the Zookeeper has quorum (min three nodes), then you have your state protected for your NiFi components that write state.  Out of all the components (processors, controller services, reporting tasks, etc), there are only about 25 that record state. The only thing that lives in memory only is component status (in, out, read, write, send, received).  These are 5 minute stats that live in memory and thus any restart of the NiFi service would set these stats back to 0.  These have nothing to do with the FlowFiles or execution of the processor. If you found this response assisted with your query, please take a moment to login and click on "Accept as Solution" below this post. Thank you, Matt ... View more