On-line tape backup using an integrated cached disk array

A file server for providing save and restore backup services to clients in a data network, said file server comprising, in combination:

• a cached disk storage subsystem including a random access cache memory and a multiplicity of disk drives;
• a tape silo;
• a plurality of stream server computers linking the cached disk storage subsystem to the data network for transfer of data between the cached disk storage subsystem and the data network, said stream server computers also linking the tape silo to the cached disk storage subsystem for the transfer of data between the cached disk storage subsystem and the tape silo, wherein each of the stream server computers has a first data link to the cached disk storage subsystem and a second data link to said tape silo;
• and
• a controller server for receiving a save or restore backup service request from a client in the data network, for performing volume management and scheduling for the backup service request, and for selecting one of the stream server computers to receive backup data from the client in response to a save backup service request or to transmit the backup data to the client in response to a restore backup service request, and further in response to the save backup service request, for prestaging the backup data from the client into the cached disk storage subsystem and at a later time staging the backup data into the tape silo by transfer of the backup data from the cached disk storage subsystem to the tape silo;
• wherein said controller server includes a processor programmed for executing a volume manager program for the save and restore backup services and a scheduler program for the save and restore backup services, and said stream server computers are programmed for executing a data mover program for the save and restore backup services, and said volume manager program references a catalog in the cached disk storage subsystem, said catalog identifying disk and tape storage locations of the backup data.

A method of operating a file server for providing tape backup service to clients in a data network, said file server including a cached disk storage subsystem having a random access cache memory and a multiplicity of disk drives, a tape silo linked to the cached disk storage subsystem for data transfer between the cached disk storage subsystem and the tape silo, and a plurality of stream server computers linking the cached disk storage subsystem to said data network for the transfer of data streams between the cached disk storage subsystem and said data network, said method comprising the steps of:

• (a) receiving a backup request from a client in the data network;
• (b) streaming backup data from the client to the cached disk storage subsystem through one of said stream server computers;
• and
• (c) transferring the backup data from the cached disk storage subsystem to tape storage in the tape silo.

A method of operating a file server for providing save and restore backup services to clients in a data network, said file server including a cached disk storage subsystem having a random access cache memory and a multiplicity of disk drives, a tape silo, a plurality of stream server computers linking the cached disk storage subsystem and tape silo to the data network for transfer of data among the cached disk storage subsystem, the tape silo, and the data network, and a controller server for controlling the cached disk storage subsystem, said tape silo, and said stream server computers, said method comprising the steps of:

• (a) said controller server receiving a backup request from a client in the data network;
• (b) said controller server responding to said backup request by selecting a first one of said stream server computers for streaming backup data from the client to the cached disk storage subsystem;
• and
• (c) said controller server scheduling a transfer of the backup data from the cached disk storage subsystem to said tape silo, said transfer of the backup data from the cached disk storage subsystem to said tape silo being performed by a second one of said stream server computers reading the backup data from the cached disk storage subsystem and writing the backup data to tape storage in said tape silo.

A video file server for providing video-on-demand service and save and restore backup services to clients in a data network, said file server comprising, in combination:

• a disk storage subsystem;
• a tape silo linked to the disk storage subsystem for the transfer of data from the disk storage subsystem to the tape silo;
• a plurality of stream server computers linking the disk storage subsystem and tape silo to the data network for transfer of data between the disk storage subsystem and the data network and between the tape silo and the data network;
• and
• a controller server for receiving video-on-demand service requests and save or restore backup service requests from clients in the data network, for performing admission control and scheduling for the video-on-demand requests, for performing volume management and scheduling for the backup service requests, and for selecting one of the stream server computers to receive backup data from a client in response to each save backup service request and for selecting one of the stream server computers to transmit the backup data to a client in response to each restore backup service request, and further in response to each save backup service request, for prestaging the backup data into the disk storage subsystem and at later time staging the backup data into the tape silo from the disk storage subsystem.

A method of operating a video file server for providing video-on-demand service and save backup services to clients in a data network, said video file server including a disk storage subsystem, a tape silo linked to the disk storage subsystem for data transfer between the disk storage subsystem and the tape silo, and a plurality of stream server computers linking the disk storage subsystem to the data network for the transfer of data streams between the disk storage subsystem and the data network, said method comprising the steps of:

• receiving video-on-demand requests and save backup requests from clients in the network;
• and
• in response to the video-on-demand requests, streaming video data isochronously from the disk storage subsystem to the network;
• and
• in response to each save backup request from a client in the data network, streaming backup data from network to the disk storage subsystem through one of said stream server computers, and then transferring the backup data from the disk storage subsystem to the tape silo.

A method of operating a video file server for providing video-on-demand service and save and restore backup services to clients in a data network, said video file server including a disk storage subsystem, a tape silo linked to the disk storage subsystem for data transfer between the disk storage subsystem and the tape silo, and a plurality of stream server computers linking the disk storage subsystem to the data network for the transfer of data streams between the disk storage subsystem and the data network, said method comprising the steps of:

• receiving video-on-demand requests and save and restore backup requests from clients in the network;
• and
• in response to the video-on-demand requests, streaming video data isochronously from the disk storage subsystem to the network;
• in response to each save backup request from a client in the data network, streaming backup data from the network to the disk storage subsystem through one of said stream server computers, and then transferring the backup data from the disk storage subsystem to the tape silo;
• and
• in response to each restore backup request from a client in the data network, streaming backup data from the tape silo through one of the stream server computers to the network.

A method of operating a video file server for providing video-on-demand service and save and restore backup services to clients in a data network, said video file server including a cached disk storage subsystem having a random access cache memory and a multiplicity of disk drives, a tape silo linked to the disk storage subsystem for data transfer between the cached disk storage subsystem and the tape silo, and a plurality of stream server computers linking the cached disk storage subsystem to the data network for the transfer of data streams between the disk storage subsystem and the data network, said method comprising the steps of:

• receiving video-on-demand requests and save and restore backup requests from clients in the network;
• and
• in response to the video-on-demand requests, streaming video data isochronously from the cached disk storage subsystem to the network;
• in response to each save backup request from a client in the data network, streaming backup data from the network to the cached disk storage subsystem through one of said stream server computers, and then transferring the backup data from the cached disk storage subsystem to the tape silo;
• and
• in response to each restore backup request from a client in the data network, streaming backup data from the tape silo through one of the stream server computers to the network;
• wherein the cached disk storage subsystem acknowledges completion of a save backup operation as soon as the backup data are written to the cached disk storage subsystem;
• and
• wherein the backup data are transferred from the cached disk storage subsystem to tape storage in the tape silo during a back ground process during off-peak hours when the stream server computers are not heavily loaded by data transfers to and from the clients in the data network.