A method comprising: storing, within a storage system that is operatively coupled to a server machine that is executing a database server instance 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 ; wherein the mirror-format is different than the persistent-format; in response to a query, received by the database server instance , that requires access to the set of data, performing the steps of: causing the database server instance 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 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 ; wherein the mirror-format is different than the persistent-format; in response to a query, received by the database server instance , that requires access to the set of data, performing the steps of: causing the database server instance 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 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. <EOS>