Electrical computers and digital processing systems: memory – Storage accessing and control – Control technique
Reexamination Certificate
1999-07-14
2002-09-17
Yoo, Do Hyun (Department: 2187)
Electrical computers and digital processing systems: memory
Storage accessing and control
Control technique
C711S161000, C707S793000, C714S006130
Reexamination Certificate
active
06453396
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates, in general, to the field of computer storage technology. More particularly, the present invention relates to a system, method and computer program product for saving, or backing up, data from a computer disk drive to a tape backup system as expeditiously as possible.
Modern computers perform a variety of tasks. Obviously, for example, computers perform computations. Most recently, computers have also gained popularity as communication devices, providing electronic mail (“e-mail”) and internet access capabilities. No less important, however, is a computer's capability of storing and managing large amounts of data, such as on a magnetic disk, a compact disk read only memory (“CDROM”) or a magnetic tape.
Mass data storage is a crucial aspect of modern computer usage. For example, a bank typically stores large volumes of data, including customer records, financial market data, and internal business records, in large interconnected computer systems. Current data is generally stored in primary storage media, such as memory arrays, magnetic hard disks or optical disks, for rapid access. In many organizations, however, this data is regularly archived (or “backed-up”) on archive media, such as alternate magnetic or optical disks or for larger volumes on magnetic tape, to preserve the data for future access. Preferably, the current data is copied from the primary storage media in the computer system to the archive media. The archive media is then stored in a safe location, preferably off-site, to protect the archived data from destruction. In this manner, the existence of the current data on both the primary storage media and the archive media minimizes the risk of losing the data. For example, a fire at the bank could destroy the copy of the data in the primary storage media, but the archived data copy would still be intact. The bank could then load the archived data into the computer system to recover most of the necessary data. In the recovery process, data recorded on the tape is typically read from the tape and re-recorded on a primary storage medium.
Data recorded onto a magnetic tape is typically organized into a specific tape format. Tape formats can vary according to tape types (e.g., ½ inch, ¼ inch, and 8 mm magnetic tape). For example, on a ½ inch reel tape, data bytes are typically recorded in parallel data records onto the nine track tape. The number of bytes in a physical data record vary between one and 65,535 bytes. The available tape formats for ½ inch reel tapes generally include 800 BPI (Bytes Per Inch), 1,600 BPI, and 6,250 BPI. Actual storage capacity is a function of the recording format and the length of the tape reel. In contrast, on a ½ inch cartridge tape, data is recorded serially onto the ½ inch cartridge tape. The data records are recorded on cartridge tape tracks in a serpentine manner. As one track is completed, the recording drive switches to the next track and begins writing in the opposite direction, eliminating the wasted motion of rewinding. The number of bytes per data record is determined by the physical data record size specified by the recording device. Accordingly, the tape format in which data is to be recorded onto or read from the tape can affect, among other characteristics, storage capacity, transfer rate, data organization, and the mechanical movement of the tape during recording.
As the amount of data residing in the computer system increases, however, the time and computer resources required to archive the data also increase. In many circumstances, for example, back-up procedures are performed after normal work hours to minimized the impact on the performance of the computer system during the normal business day. In a typical configuration, data stored on one or more magnetic hard disks is read into a host computer system and organized (i.e., formatted) to be compatible with a particular tape data format. The host system then records the formatted data onto the magnetic tape. This continuous involvement of the host system in the back-up process consumes substantial host system computing cycles and decreases the host system's performance in other processes. Furthermore, to process the data at rates sufficient to keep up with the streaming speed of the tape, the involvement of the host system, including communication to and from the host system, becomes a bottleneck. Consequently, need exists for a system and method to minimize the host system involvement in the tape backup and recovery processes, particularly during the transfer of the data to and from the source storage medium to the tape.
Conventional backup operations in computer systems incorporating one or more storage controllers operating under host supervision have included a backup program that performed the necessary backup operations through the storage controller. Although relatively fast, it suffered from the requirement that the storage devices to be backed up had to be removed from host access for the entire duration of the backup operation. Moreover, the process could not identify storage devices that were then in use which resulted in the saving of storage space that was not being used. The net result was an effective consumption of excess tape storage resources and ultimately slower performance.
Alternative host-based storage solutions required the central processing unit (“CPU”) to move large amounts of data into and out of main memory. This required the use of large amounts of CPU cycles, caused data to be moved twice over the storage system interconnects (to get the data into and out of main memory) and often could not drive the associated storage devices at their peak performance.
It would, therefore, be highly desirable to utilize the computing power in high performance storage controllers to increase the performance of disk-to-tape online backup operations.
SUMMARY OF THE INVENTION
The present invention utilizes the computing power of present day high performance storage controllers in conjunction with host computer based computer program products to increase the performance of disk-to-tape online backup operations. Through the collaborative use of a storage controller and host-based software, a high performance on-line backup solution has been provided which, in a particular implementation thereof, resulted in a four times increase in backup bandwidth over conventional host based solutions while concomitantly reducing the load on the host processor from 100% during traditional backup operations to less than 10%.
By splitting the backup process into a host-based component and a storage controller component, a number of traditionally encountered problems have been ameliorated. First, the system and method of the present invention allows the host component to interact with other processes in the host environment to prevent deadlocks and data access conflicts. Secondly, it allows a user to monitor the progress of the backup operation and stop it if necessary. Thirdly, it allows for the identification of data that might require some other sort of operation performed on it. By essentially freeing up some computing power from the host to address these issues, the task of the storage controller can be optimized to move data to tape as quickly and efficaciously as possible.
The system and method of the present invention provides a host-based computer program implemented functionality that enables part of the backup operation to be performed by the host itself while concurrently utilizing specially implemented storage controller based functions to perform the backup operation. This is effectuated by providing the storage controller with a command that allows for the transfer of a contiguous group of disk drive blocks to a tape drive. Reading groups of contiguous blocks is the optimal way to read data from a disk, and by sending the storage controller groups of contiguous blocks, the task of the storage controller is kept simple so that it can be optimized and is ea
Boone Steven E.
Peters Steven J.
Compaq Computer Corporation
Hogan & Hartson LLP
Kubida William J.
Lembke Kent A.
Moazzami Nasser
LandOfFree
System, method and computer program product for hardware... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with System, method and computer program product for hardware..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and System, method and computer program product for hardware... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2886383