JPH0158532B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Technical Field of the Invention The present invention relates to a magnetic disk device that divides one physical volume into multiple logical volumes, and particularly relates to a magnetic disk device that divides one physical volume into multiple logical volumes. The present invention relates to a control method for a magnetic disk device having a plurality of logical volumes, which can perform exclusive control without changing the software of a host device.

(b) Background of the Technology FIG. 1 shows an example of the configuration of a magnetic disk subsystem in which a magnetic disk device 7 is shared by a plurality of host devices. Information processing systems 1 and 2 control magnetic disk controllers 3 and 4 to access magnetic disk device 7 via adapters 5 and 6, respectively. In this case, the system of information processing system 1 and system 2 may compete with each other, so exclusive control is performed.
Normally, this exclusive control is performed by a channel command driving a microprogram of the magnetic disk controller 3 or 4, and the following control is directly executed by the microprogram.

Figure 2 shows an example of control by a series of command chains starting with START IO. First, the command from the information processing system 1 or 2, and the start IO, cause the magnetic disk controller 3 to
Or 4 is the select device (SELECT
Select the desired magnetic disk device 7 (SELECTED) in DEVICE, and
Long connection (LONG)
CONNECTION) state. At this time, if you try to select the magnetic disk device from the interface of another system, it will be rejected because it is busy. Next, use SET ASSIGN to assign the magnetic disk drive in question (a state in which the use of the ASSIGNED magnetic disk drive is assigned), and thereby perform separation control (the magnetic disk drive is separated from the magnetic disk control device). The magnetic disk device in question (in a state in which it is executing an independently given command) is placed in a busy state from an interface of another system.
Next, in response to an ejection/separation control command such as SEEK START (start of head positioning operation), the magnetic disk device starts ejection/separation control. The long connection is canceled by the next reset long (RESET LONG), and by deselect (DESELECT), the magnetic disk device is completely disconnected from the adapter 5 or 6 and continues ejection control independently. When the separation control is completed, the magnetic disk drive issues an interrupt to the magnetic disk control device, and when the magnetic disk control device receives this, it selects the magnetic disk drive again with the select device and makes an effort to reset the interrupt. ATTENTION RESET
RESET) and perform a long connection with Setstrong. Next, reset assignment (RESET
ASSIGN) to cancel the assignment and select the next set R/
Data transfer is performed by a series of read/write commands following W (SET R/W). When the data transfer is completed, the read/write mode is canceled with reset R/W (PESET R/W), and the long connection is established with reset long. When the magnetic disk drive is released and deselected, the magnetic disk drive is disconnected, and the magnetic disk drive becomes completely free.

FIG. 3 shows a case where the magnetic disk device is reserved. When the magnetic disk control device receives a reserve command (RESERVE) from the information processing system, it selects the magnetic disk device (SELECTED) using the select device (SELECT DEVICE) and assigns it (SET).
Issue (ASSIGN) and assign (ASSIGNED)
do. Now, even if the magnetic disk device is selected from the interface of another system, it will be rejected as busy. When the magnetic disk controller receives a release command (RELEASE) from the information processing system,
Select the magnetic disk device again using the select device and assign it to RESET.
ASSIGN) to release the reserved state, and DESELECT to disconnect the magnetic disk device and make it free.

The exclusive control method described above is for the case where the magnetic disk device 7 in FIG. 1 has both one physical volume and one logical volume. When used as a computer, it is desired to be able to perform exclusive control of each logical volume without changing the software of the information processing system or the microprogram of the magnetic disk control device.

(c) Purpose of the Invention The purpose of the present invention is based on the above-mentioned request, in exclusive control of a magnetic disk device in which one physical volume is divided into a plurality of logical volumes. It is an object of the present invention to provide a control method for a magnetic disk device having a plurality of logical volumes, which is consistent with the current situation and minimizes a decrease in usage efficiency of the magnetic disk device.

(d) Structure of the Invention The present invention divides a common magnetic disk device connected to a plurality of information processing systems via respective magnetic disk control devices into a plurality of logical volumes, and divides the plurality of logical volumes into a plurality of logical volumes. In a system configuration commonly used by information processing systems, the magnetic disk control device may cause one of the plurality of information processing systems to set one of the plurality of logical volumes as a long connection by a signal indicating that one of the plurality of information processing systems has a long connection. Indicates that all of the plurality of logical volumes are to be made busy for other information processing systems, that the busy state is canceled by a signal indicating release of the long connection, and that control for separating one of the plurality of logical volumes is started. The signal makes the other logical volumes busy for all information processing systems, the signal indicating the end of the push-off control releases the busy state, and one of the information processing systems makes one of the plurality of logical volumes busy. making the logical volume busy for other information processing systems by a signal that allocates one of the logical volumes;
The present invention is characterized in that each of the plurality of logical volumes is independently and exclusively controlled by canceling the busy state using a signal indicating the release of the allocation.

(e) Examples of the invention The present invention was implemented taking into consideration the following three items.

The long connections shown in FIG. 2 indicate that they are logically connected to a host device, so when one logical volume is a long connection, the other logical volumes are also assumed to be long connections. That is, a long connection is established in units of physical volumes.

Assignments are ejection control and reserve (3rd
If this is used in units of physical volumes, while one of the logical volumes is reserved, other logical volumes cannot be used. However, since the OS recognizes that each logical volume is a separate physical volume, the job cannot be executed due to a busy timeout. Therefore, assignments are made in units of logical volumes. That is, at the time of reservation shown in FIG. 3, reserved logical volumes cannot be selected from other systems, but unreserved logical volumes must be selectable.

Having assignments in units of logical volumes contradicts the fact that during separation control, exclusive control must actually be performed in units of physical volumes. That is, during ejection control such as a seek operation, it is necessary to disconnect from the magnetic disk control device in units of physical volumes. Therefore, there is a possibility that the interrupt for the end of the ejection control will be accepted as an interrupt for another physical volume. In order to avoid this, while a certain logical volume is under separation control, all other logical volumes sharing the physical volume are kept in a busy state.

FIG. 4 is a circuit diagram showing one embodiment of the present invention. If the information processing system 1 shown in FIG. 1 is one system and the information processing system 2 is two systems, the circuit in FIG. 4 is under one system, and is operated by a control signal from one system. . 1 for terminal a
A set long command for logical volume X is input from the system, a set long command for logical volume Y is input from terminal b from one system, and
0 to set the flip-flop 16. When the flip-flop 16 is set, its output is sent to the terminals r and t via the OR circuits 23 and 24, the terminal r becomes a signal that the logic volume X from the two systems appears to be busy, and the terminal t becomes the signal that the logic volume Y becomes a signal that looks busy. When the power is turned on, a reset signal is applied to the terminal c, which resets the flip-flops 16, 17, 18, 19, and 20 through OR circuits 11, 12, 13, 14, and 15, respectively. A reset long command is input from one system to the terminal d, passes through the OR circuit 11, and resets the flip-flop 16. A set assign command for the logical volume A reset assignment command for the logical volume X is input from one system to the terminal f, and the flip-flop 17 is reset. Logic volume Y is assigned to terminal g from two systems and sent to terminal g via OR circuit 22, and a signal from one system appears to indicate that logic volume Y is busy. terminal h
A set assign command for the logical volume Y is input from the first line, and the flip-flop 18 is set. The output of flip-flop 18 is OR circuit 2
4 and is sent to terminal t. A reset assignment command for logical volume Y is input from one system to terminal i, and flip-flop 18 is reset.
Terminal j receives a logic volume Y push-off control start command from one system, flip-flop 1
9, and the output of flip-flop 19 is
It is sent to the terminal r via the OR circuit 23, and
The signal is sent to the terminal p via the OR circuit 21 and becomes a signal indicating that the logical volume X is busy from one system.
An attention reset command for logic volume Y is input to terminal k from one system, and flip-flop 19 is reset. A start command for the control of the logic volume X from one system is input to the terminal 1 to set the flip-flop 20, and the output of the flip-flop 20 is sent to the terminals q and t via OR circuits 22 and 24, respectively. An attention reset command for logic volume X is input to terminal m from one system, and flip-flop 20 is reset. Long connections of logical volumes X and Y from two systems enter terminal n and are sent to terminals p and q via OR circuits 21 and 22, respectively. Logic volume X from two systems is connected to terminal o.
is assigned and sent to the terminal p via the OR circuit 21.

FIG. 5 is a diagram illustrating how each logical volume looks from both systems when the circuit shown in FIG. 4 operates. Logical volume X from 1 system
When a command is issued, A is the state in which the logical volume Y is viewed from the first system, B is the state in which the logical volume X is viewed from the second system, and D is the state in which Y is viewed from the second system. The free state indicates a state in which access can be freely made, and indicates that no access operation will be performed unless access is made, and the busy state indicates that a busy message will be returned if access is made.

As seen in the figure, in this embodiment, even if logical volume is in a free state when viewed from either the 1st system or 2nd system, and can be used as needed. With conventional control methods, this situation is impossible; even if one logical volume is assigned, all logical volumes on the physical volume where that logical volume exists become unusable from any system. was. Comparing this point, it will be understood that this embodiment improves the usage efficiency of the magnetic disk device.

(f) Effects of the Invention As explained above, the present invention provides a method for changing the software of a host device when a plurality of host devices share a magnetic disk device that divides one physical volume into multiple logical volumes. Instead, it is possible to use exclusive control in the same way as when there is only one physical volume and one logical volume, and this has a great effect.

[Brief explanation of drawings]

Figure 1 shows an example of the configuration of a magnetic disk subsystem in which a magnetic disk device is shared by multiple host devices, Figure 2 shows an example of control using a series of command chains starting with start IO, and Figure 3 shows an example of the configuration of a magnetic disk subsystem in which a magnetic disk device is shared by multiple host devices. FIG. 4 is a circuit diagram showing an embodiment of the present invention; FIG. 5 is a view of each logical volume from both systems when the circuit shown in FIG. 4 is in operation. FIG. 1 and 2 are information processing systems, 3 and 4 are magnetic disk control devices, 5 and 6 are adapters, 7 is a magnetic disk device, and 16, 17, 18, 19, and 20 are flip-flops.

Claims (1)

[Scope of Claims] 1. A common magnetic disk device connected to a plurality of information processing systems through a magnetic disk control device, respectively, is divided into a plurality of logical volumes, and the plurality of logical volumes are connected to the plurality of information processing systems. In a system configuration that is commonly used by systems, the magnetic disk control device controls one of the plurality of logical volumes by a signal indicating that one of the plurality of information processing systems makes one of the plurality of logical volumes a long connection. making all the volumes busy for other information processing systems, releasing the busy state by a signal indicating the release of the long connection, and using a signal indicating starting the separation control of one of the plurality of logical volumes; make other logical volumes busy for all information processing systems, release the busy state by a signal indicating the end of the separation control, and allocate one of the plurality of logical volumes to one of the information processing systems; The plurality of logical volumes are individually and exclusively controlled by making the logical volume busy for other information processing systems by a signal and releasing the busy state by a signal indicating release of the allocation. A control device for a magnetic disk device having multiple logical volumes, characterized by: