Storage subsystem with configurable buffer

A storage subsystem includes a variable-size write buffer that temporarily stores write data received from a host system. The storage subsystem is capable of adjusting the size of the write buffer so as to vary both the performance (e.g., sustained write speed) of the storage subsystem and a risk of data loss. In one embodiment, the storage subsystem implements a command set that enables the host system to directly control the size of the write buffer. The storage subsystem may additionally or alternatively be capable of adjusting the size of the write buffer based on monitored operating conditions, such as the temperature, the stability/consistency of a power signal received from the host system, and/or the elapsed time since the storage subsystem was last powered up.