-By default, Arvados uses a replication factor of 2. See the @DefaultReplication@ configuration parameter in "the configuration reference":https://doc.arvados.org/admin/config.html. Additionally, each collection can be configured with its own replication factor.
+By default, Arvados uses a replication factor of 2. See the @DefaultReplication@ configuration parameter in "the configuration reference":https://doc.arvados.org/admin/config.html. Additionally, each collection can be configured with its own replication factor. It's worth noting that it is the responsibility of the Keep clients to make sure that all blocks are stored subject to their desired replica count, which is derived from the collections the blocks belong to. @keepstore@ itself does not provide replication; all it does is store blocks on the volumes it knows about. The @keepproxy@ and @keep-balance@ processes (see below) make sure that blocks are replicated properly.
+
+The maximum block size for @keepstore@ is 64 MiB, and keep clients typically combine small files into larger blocks. In a typical Arvados installation, the majority of blocks stored in Keep will be 64 MiB, though some fraction will be smaller.