Data sharing method among remote computer systems and disk control device thereof
First Claim
1. A data sharing method for sharing data between a first host computer and a second host computer, the first host computer having a first disk control device, a first database application and a first database system, the first database system including a first remote execution program, and the second host computer having a second disk control device, a second database application and a second database system, the second database system including a second remote execution program, the method comprising:
- executing a copy direction invert command to the first disk control device to invert a copy direction of data between the first disk control device and the second disk control device, wherein the first host computer executes the copy direction invert command using the first remote execution program;
executing a copy direction invert request to the second disk control device to invert the copy direction in response to the copy direction invert command, wherein the first disk control device executes the copy direction invert request;
inverting the copy direction and issuing a complete response to notify the first disk control device that inverting has occurred;
issuing a command completion response to notify the first host computer of completion of the copy direction invert command, and upon receipt of the command completion response, closing access to the first database system, such that simultaneous execution of the first database application and the second database application is prevented;
issuing a remote execution request to the second host computer in response to the command completion response, wherein the first host computer executes the remote execution request using the first remote execution control program;
executing a command to access the second disk control device in response to issuing the remote execution request to the second host computer;
determining whether or not the second disk control device is designated as a primary disk control device; and
if the second disk control device is designated as a primary disk control device, then accessing the second disk control device,wherein if the second disk control device is not designated as a primary disk control device, then the second disk control device is not accessed.
1 Assignment
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Accused Products
Abstract
A data sharing method and disk control device are ideal for running applications to process large amounts of data on remote computers in the same manner as in a database system. A disk control device contains a management table for showing the relation between a remote access identifier, a remote disk control device identifier, and command transfer control information for the remote disk control device to the disk identifier used by the host device, When a write command to write data on a designated disk is received from the host computer, the disc controller executes both a write process for writing data on a designated disk and a command transfer process for transferring a write command to the remote disk controller in accordance with command transfer control information in the management table.
24 Citations
5 Claims
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1. A data sharing method for sharing data between a first host computer and a second host computer, the first host computer having a first disk control device, a first database application and a first database system, the first database system including a first remote execution program, and the second host computer having a second disk control device, a second database application and a second database system, the second database system including a second remote execution program, the method comprising:
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executing a copy direction invert command to the first disk control device to invert a copy direction of data between the first disk control device and the second disk control device, wherein the first host computer executes the copy direction invert command using the first remote execution program; executing a copy direction invert request to the second disk control device to invert the copy direction in response to the copy direction invert command, wherein the first disk control device executes the copy direction invert request; inverting the copy direction and issuing a complete response to notify the first disk control device that inverting has occurred; issuing a command completion response to notify the first host computer of completion of the copy direction invert command, and upon receipt of the command completion response, closing access to the first database system, such that simultaneous execution of the first database application and the second database application is prevented; issuing a remote execution request to the second host computer in response to the command completion response, wherein the first host computer executes the remote execution request using the first remote execution control program; executing a command to access the second disk control device in response to issuing the remote execution request to the second host computer; determining whether or not the second disk control device is designated as a primary disk control device; and if the second disk control device is designated as a primary disk control device, then accessing the second disk control device, wherein if the second disk control device is not designated as a primary disk control device, then the second disk control device is not accessed. - View Dependent Claims (2, 3)
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4. A data sharing method for sharing data between a first host computer and a second host computer, the first host computer having a first disk control device, a first database application and a first database system, the first database system including a first remote execution program, and the second host computer having a second disk control device, a second database application and a second database system, the second database system including a second remote execution program, and wherein said first disk control device includes a first control table containing a pair of disk identifiers for a local disk used by the first host computer and a corresponding remote disk used by said second host computer and control information indicating a copy direction in each pair of the local disk and the remote disk, and wherein said second disk control device includes a second control table containing the pair of disk identifiers and said control information, the method comprising the steps of:
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executing, in said first disk control device, a first data write command issued from said first host computer to update the stored data of the local disk and transmitting the first data write command to said second disk controller to update data of the remote disk, which corresponds to data updated by said first disk control device, according to the copy direction designated by said control information in said first control table; executing a control procedure for inverting the copy direction by changing said control information on said first and second control tables in response to a copy direction invert command issued by said first host computer using the first remote execution program; issuing a command completion response to notify the first host computer of completion of the control procedure for inverting the copy direction, and upon receipt of the command completion response, closing access to the first database systems, such that simultaneous execution of the first database application and the second database application is prevented; issuing a request for remote data processing, wherein said first host computer issues said request to said second host computer, and wherein the first host computer requests the remote data processing using the first remote execution program; determining whether or not the control information indicates that the second disk control device is a primary disk control device; and if the control information indicates that the second disk control device is a primary disk control device, then in response to a second data write command issued by said second host computer based on the request for remote data processing, writing data onto the remote disk to update data stored in the remote disk and transmitting the second data write command to the first disk controller in order to update data of the local disk, which is corresponding to data updated by said second disk control device, according to the reversed copy direction designated by the changed control information in said second control table, wherein if the control information does not indicate that the second disk control device is a primary disk control device, then data is not written onto the remote disk. - View Dependent Claims (5)
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Specification