Under the "rolling" history mode, does the size of a node's stored data remains roughly constant in time? If yes, what is the size currently?
When running a node, the
store is responsible of storing blocks (headers, operations, …) and the
context stores the ledger state (balances, contracts, …).
In the current rolling mode implementation, only the store is cleaned on regular basis (at the beginning of a new cycle). Indeed, the garbage collection (deletion of unreachable elements) of the context is not currently efficient enough to be implemented in the node release. A new storage back-end is currently developed and tested to allow a more reliable context cleaning.
In terms of storage consumption, the store size should increase during a cycle and remain roughly constant between each cycles starts (when triggering the cleanup). The same behavior (modulo new accounts, contracts, …) is expected on the context with the future back-end.
It is quite difficult to give precise figures as it vary regarding the network load and the protocol.