US 6,549,992 B1 · Computer data storage backup with tape overflow control of disk caching of backup data stream

Abstract

A data storage system is constructed to rapidly respond to a backup request by streaming backup data from primary storage to tape. It is desirable to permit the data to be removed from the primary storage at a faster rate than it can be written to tape. The backup data is buffered in a memory buffer, and when the memory buffer becomes substantially full, a portion of the backup data is buffered in disk storage. When the memory buffer becomes substantially empty, the portion of the backup data in the disk storage is written to tape. In a preferred embodiment, the memory buffer is in random access memory of a data mover computer that transfers the backup data from primary storage to a tape library unit. When the memory buffer becomes full, the data mover stores the overflow in a cached disk storage subsystem. When the memory buffer becomes empty, the data mover retrieves the overflow from the cached disk storage subsystem and transmits the overflow to the tape library unit. In this fashion, the sequence of data tracks as stored on the tape can be different from the sequence of data tracks as stored in the primary storage. To facilitate restoration of the primary storage with a backup version, the data tracks as stored in records on the tape are identified by a track number included in each record on the tape.

Claims41

Dependent claims

In a data processing system including primary data storage accessible to a host processor for read/write access and a tape storage device for providing backup storage on a tape by transfer of backup data from the primary data storage to the tape in response to a backup request, a method of selective buffering of the backup data from the primary data storage before the backup data is written to the tape, said method comprising:

a) transferring a first portion of the backup data from the primary data storage to a memory buffer and from the memory buffer to the tape;
and
b) when the backup data is delivered from the primary data storage to the memory buffer at a faster rate than the backup data is written from the memory buffer to the tape, preventing overflow of the memory buffer by transferring a second portion of the backup data from the primary data storage to intermediate disk storage, and at a later time transferring the second portion of the backup data from the intermediate disk storage to the tape.

In a data storage system including at least one data mover computer receiving a stream of backup data from a data storage device, a cached disk storage subsystem coupled to the data mover computer for intermediate data storage, and a tape library unit coupled to the data mover computer for storage of the backup data onto a tape, a method of selective buffering of the backup data from the data storage device before the backup data is written to the tape, said method comprising:

a) transferring a first portion of the backup data from the data storage device to a random access memory buffer in the data mover computer and from the random access memory buffer to the tape;
and
b) when the backup data is delivered from the data storage device to the random access memory buffer at a faster rate than the backup data is written from the random access memory buffer to the tape, preventing overflow of the random access memory buffer by transferring a second portion of the backup data from the data mover computer to the cached disk storage subsystem, and at a later time transferring the second portion of the backup data from the cached disk storage subsystem to the tape.

A data storage system comprising:

a tape library unit including at least one tape;
at least one data mover computer adapted for receiving a stream of backup data from a data storage device and coupled to the tape library unit for transferring the backup data to the tape library unit for writing the backup data onto the tape;
and
a cached disk storage subsystem coupled to the data mover computer for receiving data from the data mover computer, and coupled to the tape library unit for writing data from the cached disk storage subsystem to the tape library unit;
wherein the data mover computer includes a random access buffer memory, and wherein the data mover computer is programmed to control a flow of the backup data to the random access memory buffer and to the cached.disk storage subsystem so that when the backup data is delivered to the random access memory buffer at a faster rate than the backup data is transferred from the random access memory buffer to the tape library unit, overflow of the random access memory buffer is prevented by buffering a portion of the backup data in the cached disk storage subsystem for transfer to the tape library unit at a later time.

2 more elements

A program storage device containing a program executable by a data processor for selectively buffering a stream of data from a data source to a data sink by buffering the data in a buffer memory or in disk storage,

the program being executable by the data processor for buffering the data in the memory buffer unless the memory buffer becomes substantially full, and when the memory buffer becomes substantially full, buffering a portion of the data from the data source in the disk storage, and
the program being executable by the data processor for supplying data to the data sink from the buffer memory unless the memory buffer becomes substantially empty, and when the memory buffer becomes substantially empty, supplying the portion of the data from the disk storage to the data sink.

Dependencies are inferred from the claim text.

Computer data storage backup with tape overflow control of disk caching of backup data stream

Life of this patent

Computer data storage backup with tape overflow control of disk caching of backup data stream

Life of this patent

Abstract

Claims41