Electrical computers and digital processing systems: memory – Addressing combined with specific memory configuration or... – Dynamic-type storage device
Reexamination Certificate
2000-03-03
2002-11-19
Yoo, Do Hyun (Department: 2187)
Electrical computers and digital processing systems: memory
Addressing combined with specific memory configuration or...
Dynamic-type storage device
C711S152000, C710S120000
Reexamination Certificate
active
06484229
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a control system of logical units present in a disk storage apparatus, and to a computer system comprising the disk storage apparatus and one or a plurality of host computers.
2. Description of the Related Art
A computer system, in which one or a plurality of disk storage apparatuses having a plurality of logical units are connected to a plurality of host computers through high-speed interfaces such as a Fibre Channel and these host computers share one or a plurality of disk storage apparatuses, is known. However, there is a strong demand in such a computer system for storing information inherent to each host computer, such as an OS, in the disk storage apparatus having a high-speed interface, such as a Fibre Channel, and shared by a plurality of host computers, rather than in a disk storage apparatus having an ATA (Advanced Technology Attachment) or SCSI (Small Computer System Interface) interface and connected discretely to each host computer, from the aspects of high-speed performance and cost. In order to store the information inherent to each host computer in the disk storage apparatus shared by a plurality of host computers, it is essentially necessary to control exclusively the logical unit, that stores the information inherent to each host computer, as the logical unit dedicated to the individual host computer.
When a plurality of host computers and one or a plurality of disk storage apparatuses are connected by the Fibre Channel, the physical interface is generally the Fibre Channel and the logical interface is generally the SCSI.
In the SCSI, a Reserve/Release command and a Persistent Reserve In/Out command are stipulated as the commands for exclusively managing the logical units. However, to manage exclusively the logical unit dedicated to each host computer for other host computers in these SCSI commands, the following problems are yet to be solved.
In the Reserve/Release command, the Reserve condition of the logical unit is released if the power source of the disk storage apparatus is cut off or the disk storage apparatus is reset. Therefore, the logical unit dedicated to each host computer cannot be managed exclusively at the time of making of the power source.
In the Persistent Reserve In/Out command, the Persistent Reserve condition is not released even when the power source of the disk storage apparatus is cut off or the disk storage apparatus is reset. However, because other host computer holding a Reservation Key can change the Persistent Reserve condition, the logical unit dedicated to each host computer cannot completely be managed exclusively.
To manage exclusively the logical unit dedicated to each host computer, a mechanism becomes necessary that exclusively manages the logical unit inside the disk storage apparatus without relying on exclusive management by the SCSI command.
Conventional control systems of the logical units of the disk storage apparatuses are described in “SCSI Bus System” (JP-A-6-44181) and “Conversion Method of Block Address and Control Method of Rotary Type Storage Sub-System” (JP-A-9-62452), for example. When this control system is constituted by the conventional disk storage apparatus, there is no other means at present than the method using Reserve/Release command or the Persistent Reserve In/Out command of the SCSI in order to exclusively manage the logical units. Therefore, it has not been possible to completely manage exclusively the logical unit dedicated to each host computer.
On the other hand, in the conventional disk storage apparatuses and host computers, the logical disk number that is assigned for managing the logical disk inside the disk storage apparatus is coincident with the logical disk number assigned for managing the logical disk inside the host computer. If the host computer designates the same logical unit number, therefore, access is made to the same logical unit inside the disk storage apparatus when all the host computers gain access to this logical unit.
When the host computer and the disk storage apparatus are connected mutually through the interface, the host computer designates serially the logical unit numbers from 0 to each disk storage apparatus at the time of making of the power source, sends the Inquiry command of the SCSI and recognizes the disk storage apparatus and the logical unit inside the disk storage apparatus. Generally, the host computer keeps sending the Inquiry command serially from the logical unit number 0 until it detects from the response of the Inquiry command that the logical unit in the designated disk storage apparatus does not exist. Therefore, the serial numbers are allotted to the logical units inside the host computer, and the logical units are so managed.
In such a computer system, there is a strong demand for storing a shared application and data, that are used in the computer system, in the disk storage apparatus that has a high-speed interface such as the Fibre Channel and is shared by a plurality of host computers, from the aspects of maintenance and the cost. Generally, the conventional disk storage apparatuses incorporate the logical unit having the number 0.
SUMMARY OF THE INVENTION
In a computer system in which a plurality of host computers share one or a plurality of disk storage apparatuses, an object of the present invention is that it proposes an internal mechanism of a disk storage apparatus that exclusively manages its logical units for the host computers without using an SCSI command for exclusive management.
The disk storage apparatus includes a hard disk drive and a disk array. The hard disk drive comprises a disk control portion and a disk drive. The disk control portion comprises a host interface control portion, a host management portion, a logical unit management portion, an address conversion portion, a command processing portion, a drive cache, a drive cache control portion, a drive control portion and a data bus.
The disk array has a mechanism that achieves high performance and high reliability of the disk system. To attain high-speed performance, a physical hard disk drive is allowed to function apparently as one hard disk drive for the host computer in the disk array. To attain high reliability, on the other hand, redundant data for data recovery is stored in other hard disk drive if any trouble occurs in the hard disk drive that stores the data.
The disk array comprises one or a plurality of disk array controllers and a plurality of hard disk drives. Fibre Channel, SCSI, and so forth are used as the interface between the disk array controller and a plurality of hard disk drives. Each disk array controller comprises a host interface control portion, a host management portion, a logical unit management portion, an address conversion portion, a command processing portion, a drive interface control portion, a drive cache and a drive cache control portion.
In order to achieve the object of the present invention, in a computer system in which a plurality of host computers and one or a plurality of disk storage apparatuses having a plurality of logical units are connected to one another by the Fibre Channel as the physical interface and by SCSI as the logical interface in FC-AL (Fibre Channel Arbitrated Loop) topology, a disk storage apparatus according to the present invention includes a logical unit correspondence memory portion for storing the correspondence between the logical unit number allotted by and in the host computer and the logical unit number allotted by and in the disk storage apparatus, and a logical unit number conversion portion for converting the logical unit number designated by the corresponding host computer through the SCSI command by using the logical unit correspondence memory portion to the logical unit number in the disk storage apparatus, both portions being provided to the logical unit management portion of the disk storage apparatus. The logical unit management memory portion includes a logical unit correspondence setting portion for setting the
Honda Kiyoshi
Ichikawa Masatoshi
Kamimaki Hideki
Kunisaki Osamu
Matsunami Naoto
Mattingly Stanger & Malur, P.C.
Namazi Mehdi
Yoo Do Hyun
LandOfFree
Magnetic disk apparatus does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Magnetic disk apparatus, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Magnetic disk apparatus will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2977796