1. A data management appliance, comprising: a random-access storage unit; and control circuitry adapted to receive commands from a host computer system, wherein in response to the control circuitry receiving a write command from the computer system, the control circuitry updates the random-access storage unit to include information associated with the write command and in response to a read command including a logical address and a time value, the control circuitry retrieves, from the random-access storage unit, data representing contents of the logical address at a time represented by time value.