Snapshots in a hybrid storage device comprising a magnetic disk and a solid state disk

摘要

One or more snapshots of data stored over a period of time are maintained in a hybrid storage device comprising a magnetic disk and a solid state disk, wherein a selected snapshot stores information that allows recovery of data that is stored in the hybrid storage device at a selected point in time of the period of time. The hybrid storage device receives an input/output (I/O) command from a computational device. A category of a plurality of categories to which the I/O command belongs is determined, wherein the plurality of categories comprise writing to an unused block, writing to a used block, reading from an unused block, and reading from a used block. In response to determining the category to which the I/O command belongs, the I/O command is handled by one of the magnetic disk and the solid state disk based on the determined category.

主权项

1. A method, comprising:
maintaining one or more snapshots of data stored over a period of time in a hybrid storage device comprising a magnetic disk and a solid state disk, wherein the magnetic disk and the solid state disk are maintained within a single housing that implements the hybrid storage device, and wherein a selected snapshot stores information that allows recovery of data that is stored in the hybrid storage device at a selected point in time of the period of time; receiving, by the hybrid storage device, an input/output (I/O) command from a computational device; determining, by an application that executes in software, firmware, or hardware maintained within the single housing that implements the hybrid storage device, a category of a plurality of categories to which the I/O command received from the computational device belongs, wherein the plurality of categories comprise writing to an unused block, writing to a used block, reading from an unused block, and reading from a used block, and wherein the used block is a block on which data has been written; in response to determining by the application executing in the hybrid storage device the category to which the I/O command received from the computational device belongs, handling the I/O command by one of the magnetic disk and the solid state disk based on the determined category; and in response to determining that an incremental snapshot stored in the solid state disk is to be merged with a first snapshot stored in the magnetic disk, all blocks in the incremental snapshot stored in the solid state disk are copied onto the magnetic disk to overwrite oldest blocks present in the magnetic disk, wherein: management of snapshots is provided by a management software that resides in a hidden partition of the magnetic disk and is loaded prior to operating system startup by Extensible Firmware Interface or Basic Input-Output System, and once the management of snapshots is complete the operating system is loaded.