In case all Cassandra nodes associated with a DMA are down, database files will be offloaded to the system cache folder on disk, and will be pushed to the database once the connection becomes available again.
I wonder if there is a way to manually enable the offload while the database is up and running?
For debugging purposes, I'd like to see what exactly is being pushed to the database in terms of trend data, element data, etc..., without having to temporarily disconnect the database.
Not really what you asked for, but you can enable tracing on Cassandra to track history queries.
More details can be found here.
Do keep in mind that this should only be enabled temporarily, as it has a major impact on the system performance.