The transactor does limit write scaling. However, compared to a typical database server, the transactor doesn’t have to handle all the other work normally done by a server (servicing queries and reads, locking, disk sync etc), and many workloads will be supported by this configuration. Datomic doesn’t target the very highest write volumes, as those workloads require different tradeoffs (one or more of: a loss of transactions, queries, or consistency, and/or the need to shard).