A method comprising: storing, within a storage system that is operatively coupled to a server machine that is executing a database server instance (106, 166) that manages a database: a persistent-format copy of a set of data, in a persistent-format, on persistent storage of the storage system; and a mirror-format copy of the set of data, in a mirror-format, in volatile memory of the storage system; wherein the storage system is separate from the server machine; wherein the set of data is from a table in the database managed by the database server instance (106, 166); wherein the mirror-format is different than the persistent-format; in response to a query, received by the database server instance (106, 166), that requires access to the set of data, performing the steps of: causing the database server instance (106, 166) to communicate a task to the storage system; and the storage system performing the task using the mirror-format copy; in response to the mirror-format copy being evicted from the volatile memory of the storage system, the storage system copying the mirror-format copy from the volatile memory to another storage tier of the storage system, wherein the other storage tier has slower access rates than the volatile memory and faster access rates than the persistent storage, thus enabling the mirror-format copy to be accessed with less overhead than would be required to rebuild the mirror-format copy from scratch in the volatile memory based on the persistent-format copy. storing, within a storage system that is operatively coupled to a server machine that is executing a database server instance (106, 166) that manages a database: a persistent-format copy of a set of data, in a persistent-format, on persistent storage of the storage system; and a mirror-format copy of the set of data, in a mirror-format, in volatile memory of the storage system; a persistent-format copy of a set of data, in a persistent-format, on persistent storage of the storage system; and a mirror-format copy of the set of data, in a mirror-format, in volatile memory of the storage system; wherein the storage system is separate from the server machine; wherein the set of data is from a table in the database managed by the database server instance (106, 166); wherein the mirror-format is different than the persistent-format; in response to a query, received by the database server instance (106, 166), that requires access to the set of data, performing the steps of: causing the database server instance (106, 166) to communicate a task to the storage system; and the storage system performing the task using the mirror-format copy; causing the database server instance (106, 166) to communicate a task to the storage system; and the storage system performing the task using the mirror-format copy; in response to the mirror-format copy being evicted from the volatile memory of the storage system, the storage system copying the mirror-format copy from the volatile memory to another storage tier of the storage system, wherein the other storage tier has slower access rates than the volatile memory and faster access rates than the persistent storage, thus enabling the mirror-format copy to be accessed with less overhead than would be required to rebuild the mirror-format copy from scratch in the volatile memory based on the persistent-format copy.