The Aurora operating system: revisiting the single level store

Applications on modern operating systems manage their ephemeral state in memory, and persistent state on disk. Ensuring consistency between them is a source of significant developer effort, yet still a source of significant bugs in mature applications. We present the Aurora single level store (SLS), an OS that simplifies persistence by automatically persisting all traditionally ephemeral application state. With recent storage hardware like NVMe SSDs and NVDIMMs, Aurora is able to continuously checkpoint entire applications with millisecond granularity. Aurora is the first full POSIX single level store to handle complex applications ranging from databases to web browsers. Moreover, by providing new ways to interact with and manipulate application state, it enables applications to provide features that would otherwise be prohibitively difficult to implement. We argue that this provides strong evidence that manipulation and persistence of application state naturally belong in an operating system.