Efficient application recovery in an information management system based on a pseudo-storage-device driver

A method comprising:

• executing an application on a client computing device substantially concurrently with restoring a backup copy of primary data previously generated by the application, based on:
• (i) restoring the backup copy from a secondary storage device to a destination volume configured on a primary storage device that is mounted to a first mount point of the client computing device;
• (ii) while the restoring operation is proceeding to the destination volume, executing the application on the client computing device, based on using a pseudo-volume as a store for primary data, wherein the pseudo-volume is also mounted to the first mount point of the client computing device after the primary storage device is mounted, and
• wherein the pseudo-volume comprises a first data structure for storing first data blocks retrieved from the backup copy on the secondary storage device in response to read requests for the first data blocks issued by the executing application, and
• further comprises a second data structure for storing second data blocks included in write requests issued by the executing application;
• (iii) after the restoring of the backup copy to the destination volume is completed, (a) stopping the application, (b) unmounting the pseudo-volume from the first mount point, and (c) updating the destination volume with data blocks stored in the second data structure, including the second data blocks;
• and
• executing the application again, on the client computing device, based on using the updated destination volume as the application's store for primary data, thereby providing the application with access to data in the restored backup copy updated by at least the second data blocks from the second data structure, which were generated by the application while the restoring operation was proceeding;
• wherein the using of the pseudo-volume as the application's store for primary data while executing the application on the client computing device is managed by a data agent that also executes on the client computing device;
• and
• wherein the data agent executes a read request for the first data blocks issued by the application by:
• supplying the first data blocks from the second data structure when the first data blocks are found therein,
• supplying the first data blocks from the first data structure when the first data blocks were not found in the second data structure and were found in the first data structure, and
• causing the first data blocks to be fetched from the backup copy on the secondary storage device when the first data blocks were not found in either of the first data structure or the second data structure.

A system for application recovery based on using a pseudo-storage-device driver, the system comprising:

• a client computing device in communication with a primary storage device and a secondary storage device;
• wherein the client computing device is configured with a mount point, and also comprises an executable application, an executable data agent, and an executable driver;
• wherein the primary storage device comprises a storage volume that is mounted to the first mount point of the client computing device, and which is designated a destination volume for a restore operation;
• wherein the secondary storage device comprises a backup copy of primary data previously generated by the application, which backup copy is to be restored to the destination volume in the primary storage device;
• wherein the driver is configured to present a pseudo-volume mounted to the same first mount point of the client computing device used by the primary storage device;
• wherein the pseudo-volume comprises a first data structure for storing first data blocks retrieved from the backup copy on the secondary storage device in response to read requests for the first data blocks issued by the application, and further comprises a second data structure for storing second data blocks included in write requests issued by the application;
• and
• wherein, based on the pseudo-volume being mounted to the same first mount point of the client computing device as the destination volume, the system is configured to substantially concurrently (a) execute a restore operation of the backup copy from the secondary storage device to the destination volume, and (b) execute the application on the client computing device, based on using the pseudo-volume as a store for the application's primary data, configured to service the application's write requests and read requests while the restore operation proceeds;
• wherein the using of the pseudo-volume as the store for the application's primary data is managed by the data agent that also executes on the client computing device;
• and
• in response to a read request for a data block issued by the application the data agent is configured to:
• (i) supply the data block from the second data structure when the data block is found therein, (ii) supply the data block from the first data structure when the data block was not found in the second data structure and was found in the first data structure;
• and (iii) cause the data block to be fetched from the backup copy in the secondary storage device when the data block was not found in either of the first data structure and the second data structure.