JPH09258906A - Disk device connection device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize data transfer with a disk device even if a fault occurs in a low-order protocol by permitting a disk device switch control part to make a drive switch circuit provided for a low-order protocol control part select the disk device corresponding to a disk device number. SOLUTION: The disk device switch control part 50 selects low-order SCSI protocol controllers 12a-12d which are not used yet and in which the faults do not occur among the plural low-order SCSI protocol controllers 12a-12d when the disk device number is designated from a high-order device. The drive switch circuits 51a-51d provided for the selected low-order SCSI protocol controllers 12a-12d are caused to select the disk device corresponding to the disk device number. Even if the fault occurs in one of the low-order SCSI protocol controllers 12a-12d, data transfer with the disk device via the other controllers can be executed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a disk device connection device, and more particularly to a plurality of magnetic disk devices connected to a host device by a SCSI interface bus.
The present invention relates to a disk device connection device for connecting a table or a plurality of host devices.

[0002]

2. Description of the Related Art FIG. 3 is a block diagram showing an example of a conventional connection system between a magnetic disk device and a host device.

The bus connection control circuit shown in FIG.
Interface (Small Computer S
A system interface bus connects a higher-level device to a magnetic disk device (SCSI drive device).

In this conventional connection system, an upper SCSI protocol controller (upper protocol control unit) which communicates with a higher device and a plurality of lower devices which communicate with each of a plurality of connected SCSI drive devices. S
A CSI protocol controller (lower protocol control unit), a lower SCSI switching circuit that switches the connection between the upper SCSI protocol controller and the lower SCSI protocol controller, and an upper SCSI lower SCSI control circuit that controls the operation of this lower SCSI switching circuit. And a plurality of bus connection control circuits having the same.

Then, different upper devices are connected to the upper SCSI protocol controller, and the lower SCSI is connected.
By connecting multiple SCSI drive devices common to the protocol controller, the multi-initiator /
Configure a multi-target system.

Thus, conventionally, a plurality of host devices and a plurality of SCSI devices have been used by using a magnetic disk device connection device.
The drive device can be simultaneously connected in an arbitrary combination to improve the operation rate of the host device.

[0007]

However, in the conventional disk device connection device, if one lower SCSI protocol controller fails, the SCSI drive device corresponding to the lower SCSI protocol controller cannot be used. There was an inconvenience.

[0008]

An object of the present invention is to connect a lower SCSI protocol controller and a SCSI drive device to a lower S
The SCSI bus output from the CSI protocol controller is designated by the upper device of the plurality of SCSI drive devices.
By switching to the SI drive device, even if the lower SCSI protocol controller (lower protocol control unit) fails, it is possible to connect to the SCSI drive device that should be selected from another path, thereby improving the system performance. That is the purpose.

[0009]

For this reason, the disk device connection apparatus according to the present invention comprises an upper SCSI protocol controller for communicating with an upper apparatus and a plurality of lower SCs.
SI protocol controller and upper and lower SCSI
Control means for controlling the protocol controller to perform communication, a plurality of SCSI drive devices, and subordinate S for performing communication
It has a CSI protocol controller and means for switching to a SCSI drive device to be selected from a plurality of SCSI drive devices. Further, the number of bus connection control circuits is plural.

Specifically, as a first means (claim 1), an upper protocol control unit for controlling data transfer with an upper device and a plurality of lower protocols for controlling data transfer with a plurality of disk devices, respectively. A control unit and a disk device switching control unit that controls connection with a plurality of disk devices based on the disk device number designated by the host device are provided. Moreover, multiple lower protocol control units
A drive switching circuit that connects the protocol control unit and a plurality of disk devices is also installed. Further, the disk device switching control unit selects an unused lower-layer protocol control unit that is unused and has not failed from the plurality of lower-layer protocol control units when the disk device number is specified by the higher-level device. Effective lower-layer protocol control unit selection And a disk device selecting means for controlling the drive switching circuit provided in the lower protocol control unit selected by the effective lower protocol control unit selecting unit to select the disk device corresponding to the disk device number. , Is adopted.

In the first means, the effective lower protocol control unit selecting means controls the lower protocol control which is unused and has not failed among the plurality of lower protocol control units when the disk device number is designated by the upper device. And the disk device selecting means controls the drive switching circuit provided in the lower protocol control unit selected by the effective lower protocol control unit selecting means to select the disk device corresponding to the disk device number. Therefore, even if a failure occurs in the lower protocol control unit, data transfer is performed via the other lower protocol control unit and the disk device provided in the failed lower protocol control unit.

In the second means (claim 2), in addition to the matter for specifying the first means, the disk device switching control section stores a plurality of use states and error output states as lower protocol control section information. The state storage means and the lower protocol control section information reference means for selecting the lower protocol control section based on the lower protocol control section information stored in the use state storage section are provided.

In the third means (claim 3), in addition to the matter for specifying the first means, when the disk device switching control unit specifies the disk device number from the upper device, the data transfer by the specification is performed. An error lower protocol control unit avoiding means for selecting another lower protocol control unit for the data transfer when an error occurs in the lower protocol control unit is adopted.

In the third means, the error lower protocol control unit avoiding unit avoids the lower protocol control unit in which the error has occurred, and the valid lower protocol control unit selecting unit selects another lower protocol control unit. To be done. Therefore, the upper device continues the processing without being affected by the error generated in the lower protocol control unit.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described in detail with reference to the drawings.

As shown in FIG. 1, the disk device connection device 9 according to the present embodiment comprises four bus connection control circuits 1a to 1d having the same structure. In the example shown in FIG. 1, a plurality of host devices can be connected to a plurality of disk devices (SCSI drive devices), respectively.

Each of the bus connection control circuits 1a to 1d has a structure shown in FIG. 2 as a representative of the bus connection control circuit 1a. The bus connection control circuit 1a controls data transfer between a higher-level SCSI controller controller (upper-layer protocol controller) 11 that controls data transfer with the higher-level device 10a and SCSI drive devices (plural disk devices) 2a to 2d. Multiple lower SCSI protocol controllers (lower protocol control units) 12a to 12d
And a disk device switching control unit 50 for controlling connection with a plurality of disk devices based on the disk device number designated by the host device.

Moreover, drive switching circuits 51a to 51d for connecting the upper SCSI protocol controller 11 and the SCSI drive devices 2a to 2d are provided in parallel with the plurality of lower SCSI protocol controllers 12a to 12d, respectively.

In the example shown in FIG. 2, the disk device switching control unit 50 is a lower SCSI protocol controller 12a.
The lower SCSI switching circuit 14 for switching between ~ 12d and the lower SCSI protocol controller 12a ~ 12d, depending on the usage status and error occurrence status of the lower SCSI protocol controller to be used for the data transfer request from the upper device, Lower SCSI switching circuit 1
4 to the lower SCSI protocol controller 12a to
Upper SCSI lower S that controls to switch 12d
CSI control circuit 13A and SC specified by the host device
Drive switching control circuit 13B for controlling the drive switching circuits 51a to 51d according to the SI drive number
And

The disk device switching controller 50 is an unused lower SCSI protocol controller 12a to 12d out of the plurality of lower SCSI protocol controllers 12a to 12d when the disk device number is designated by the upper device 10a. To the drive switching circuits 51a to 51d attached to the lower SCSI protocol controllers 12a to 12d selected by the effective lower protocol control unit selecting unit and the effective lower protocol control unit selecting unit.
And a disk device selecting means for controlling to select a CSI drive device (disk device).

Therefore, even if one of the lower SCSI protocol controllers 12a to 12d fails, the other lower SCSI protocol controllers 12a to 12d and the drive switching circuits 51a to 51d.
The detoured data transfer using 51d becomes possible.

Further, the disk device switching control unit 50 includes a use state storage means for storing a plurality of use states and error output states as lower protocol control unit information, and lower protocol control unit information stored in the use state storage unit. And a lower protocol control unit information reference means for selecting the lower protocol control unit based on the above.

Therefore, it becomes possible to reliably avoid the unusable lower SCSI protocol controllers 12a to 12d.

Further, the disk device switching control unit 50 is
When an error occurs in the lower protocol control unit for the data transfer according to the specification when the disk device number is specified by the upper device, an error lower protocol control unit avoiding means for selecting another lower protocol control unit for the data transfer is provided. I have it.

The error lower protocol control unit avoiding means avoids the lower protocol control unit in which the error has occurred, and the valid lower protocol control selecting unit selects another lower protocol control unit. Therefore,
The upper device will continue processing without being affected by the error that has occurred in the lower protocol control unit.

This will be described in detail.

Upper SCSI protocol controller 11
Communicates with a host device via the host SCSI bus 3a.

Upper SCSI protocol controller 11
And lower SCSI protocol controllers 12a-12d
Between the upper SCSI and the lower SCSI control circuit 13A
The lower SCSI switching circuit 14 that operates according to the command is provided.

Upper SCSI protocol controller 11
And lower SCSI protocol controllers 12a-12d
Is the data line 15 via the lower SCSI switching circuit 14.
Send and receive data by.

Lower SCSI Protocol Controller 12
The a to 12d are connected to the drive switching circuits 51a to 51d via the lower SCSI buses 41a to 41d, respectively.

Upper SCSI Lower SCSI control circuit 13A
Controls the upper SCSI protocol controller 11 through the upper SCSI control line 16 and controls the lower SCSI.
The protocol controller 12 is controlled by the lower SCSI control line 17. Further, the upper SCSI lower SCSI control circuit 13A sends an instruction to the lower SCSI switching circuit 14 via the lower SCSI switching control line 18 to switch the lower SCSI protocol controller 12 to be controlled.

Lower SCSI switching circuit 14 which has received the instruction
Connects the data line 15 from the upper SCSI protocol controller 11 and the lower SCSI control line 17 from the upper SCSI-lower SCSI control circuit 13 to the lower SCSI.
Connect to the protocol controller 12.

Lower SCSI Protocol Controller 12
The upper SCSI lower SCSI control circuit 13A selects a to 12d. Upper SCSI Lower SCSI control circuit 1
3A selects a lower SCSI protocol controller that is unused and has not failed.

The drive switching control circuit 13B uses the data line 5
2, the information of the selected lower SCSI protocol controller 12 and the selected SCSI drive device 2 is received from the upper SCSI lower SCSI control circuit 13A.

The drive switching control circuit 13B uses the drive switching control line 19 to drive the drive switching circuits 51a to 51a.
Then, the lower SCSI buses 41a to 41d connected to the selected lower SCSI protocol controllers 12a to 12d are switched to the lower SCSI buses 42a to 42d connected to the selected SCSI drive device 2.

In FIG. 1, four bus connection control circuits 1
a to 1d are respectively connected to the upper devices 10a to 10d via the upper SCSI buses 3a to 3d, and the bus connection control circuits 1a to 1d are respectively connected to the lower S.
The four SCSI drive devices 2a to 2d are connected via the CSI buses 42a to 42d.

Next, the operation of the magnetic disk device connection device 9 configured as described above will be described in detail with reference to FIG.

First, allocation of an identifier (ID) will be described.

Since the respective initiators and targets of the upper SCSI buses 3a to 3d are one-to-one, and the upper SCSI bus is separated for each upper device, four sets are assigned to each bus connection control circuit 1a to 1d. ID is
The same can be used. Therefore, I of the higher-level devices 10a to 10d
D is "7", each upper SC of the bus connection control circuits 1a to 1d
The ID of the SI protocol controller 11 is set to "0".

There are four sets of lower SCSI buses 42a to 42d, but one bus connection control circuit is connected to the lower SCSI protocol controllers 12a to 12d on a one-to-one basis through a drive switching circuit. Therefore, the lower SCSI protocol controller 12a-
12d and SCSI drive devices 2a-2d ID
May be the same for the four bus connection control circuits 1a to 1d.

Since one SCSI drive device is connected to the four bus connection control circuits 1a to 1d, the IDs of the lower SCSI protocol controllers 12a to 12d are set.
Must be assigned different values for each of the four bus connection control circuits 1a to 1d. Therefore, the IDs of the four SCSI drive devices 2a to 2d are all set to "0", and the lower S
For the ID of the CSI protocol controller 12,
"7" is assigned to the lower SCSI protocol controllers 12a to 12d of the bus connection control circuit 1a, and "6" is assigned to the lower SCSI protocol controllers 12a to 12d of the bus connection control circuit 1b to control the bus connection. "5" is assigned to the lower SCSI protocol controllers 12a to 12d of the circuit 1c, and the lower SCSI protocol controller 1 of the bus connection control circuit 1d is assigned.
“4” is assigned to 2a to 12d.

For example, the host device 10a with the ID "7"
Is an upper SC whose ID is "0" in the bus connection control circuit 1a.
A command is issued to the SI protocol controller 11. At this time, one logical unit number (LUN: Logic) is assigned to each of the SCSI drive devices 2a to 2d.
Al Unit Number) is assigned and the SCSI drive device to be accessed is designated by the LUN of the identify message. For example, when the LUN is "0", the SCSI drive device 2a is designated.

Upper SCSI Lower SCSI Control Circuit 13A
Collects the LUN received by the upper SCSI protocol controller 11 via the upper SCSI control line 16. Lower SCSI protocol controllers 12a-12
If d is all unused and has not failed, the upper SCSI
The lower SCSI control circuit 13A is an unused lower SCSI
Select the protocol controller 12a and select the lower SCS
It is applied to the lower SCSI switching circuit 14 via the I switching control line 18 to switch the connection between the data line 15 and the lower SCSI control line 17.

The drive switching control circuit 13B is an upper SC
SI lower SCSI control circuit 13A selected lower SCS
I protocol controller 12a and LU to access
The information of N is collected via the data line 52. The drive switching control circuit 13B uses the drive switching control line 19 to select the selected lower SCSI protocol controller 12
The connection of the drive switching circuit 51a, which is connected to a through the lower SCSI bus 41a, is switched to the LUN to be accessed.

In this case, the SCSI drive device 2a whose LUN is "0" and the lower SCSI protocol controller 12 connected via the drive switching circuit 51a.
a, the upper SCSI protocol controller 11, the upper SCSI, the lower SCSI control circuit 13A, and the drive switching control circuit 13B can communicate with each other.

Upper SCSI Lower SCSI Control Circuit 13A
Is the lower SCS of the bus connection control circuit 1a with the ID "7"
The I-protocol controller 12a is instructed to issue a command to the SCSI drive device 2a whose ID is "0". As a result, the host device 10a and the S
The line connection with the CSI drive device 2a is established, data is exchanged via the data line 15, and the command is executed.

By the drive switching control circuit 13B storing the connection status of the drive switching circuit 51a, the lower S
Since the line connection between the CSI protocol controller 12a and the SCSI drive device 2a has been established, the lower SCS
The I protocol controller 12a can receive a command end report from the SCSI drive device 2a.

Lower SCSI Protocol Controller 12
When "a" receives the command end report, the upper SCSI lower SCSI control circuit 13A instructs the upper SCSI protocol controller 11 to cause the upper device 10a to report the command end.

Lower SCSI Protocol Controller 12
Information on the usage status of a to 12d and the malfunctioning lower SCSI protocol controller is stored in the upper SCSI lower SCSI control circuit 13A. SCSI drive devices 2a-2d and drive switching circuits 51a-51d
The connection state with is stored in the drive switching control circuit 13B.

Lower SCSI Protocol Controller 12
other lower SCSI if a is in use or is out of order
When the protocol controller 12 is unused and has not failed, the upper SCSI lower SCSI control circuit 13A selects the lower SCSI protocol controller 12b,
The data line 15 and the lower SCSI switching circuit 14
The connection of the lower SCSI control line 17 is switched.

The drive switching control circuit 13B accesses the connection of the drive switching circuit 51b connected to the selected lower SCSI protocol controller 12a via the lower SCSI bus 41b, and the SCS whose LUN is "0".
Switch to the I drive device 2a.

In this case, the lower SCSI protocol controller 12b connected via the drive switching circuit 51b to the SCI drive device 2a whose LUN is "0".
And the upper SCSI protocol controller 11 and the upper SCSI lower SCSI control circuit 13A and the drive switching control circuit 13B can communicate with each other, and the lower SCSI protocol controller 1 selected by the bus connection control circuit 13
2b to issue a command to the upper SCSI 10a and SCSI drive device 2a
Since the line connection between the two is established, the command can be executed.

Upper device 10a and SCSI drive device 2
While the command is being executed with a, the other higher-level devices 10b-1
0d and the other SCSI drive devices 2b to 2d can execute commands. For example, the higher-level device 10b with ID “7” is the higher-level SCSI protocol controller 1 with ID “0” in the bus connection control circuit 1b.
SCSI drive device 2b whose LUN is "1" for 1
Specify to issue the command.

The upper SCSI lower SCSI control circuit 13A in the bus connection control circuit 1b is the same bus connection control circuit 1A.
An unused SCSI protocol controller 12a in b is selected and the connection of the drive switching circuit 51a connected to it is switched to the SCSI drive device 2b of LUN "1" which the drive switching control circuit 13B accesses. .

Lower SC selected by the bus connection control circuit 13
It instructs the SI protocol controller 12a to issue a command. By this, upper SCSI1
Since the line connection between 0b and the SCSI drive device 2b is established, the command can be executed.

Other combinations can be operated in the same manner.

The above-described embodiment is an example in which four bus control circuits are connected to one host device, and four common SCSI drive devices are connected to each of the four bus connection control circuits. One host device can connect up to seven bus connection control circuits, one bus connection control circuit can connect up to eight SCSI drive devices, and one SCSI drive device Since a maximum of 7 bus connection control circuits can be connected, in the case of the maximum combination, one host device can access 56 SCSI drive devices.

As described above, according to the present embodiment, the lower S protocol is passed through the lower SCSI protocol controllers other than the defective lower SCSI protocol controller.
The lower SCSI bus to be output from the CSI protocol controller should be selected from among the plurality of SCSI drive devices.
When switching the lower SCSI protocol controller and the SCSI drive device with a magnetic disk device connection device that connects to multiple SCSI drive devices to switch to the SI drive device, select from a different path even if the lower SCSI protocol controller fails. It can be connected to a SCSI drive device that should be used, and the system performance is improved.

[0059]

Since the present invention is constructed and functions as described above, according to the present invention, the effective lower-layer protocol control unit selecting means is capable of selecting a plurality of lower-layer protocol control units when the disk device number is designated by the upper-layer device. Of these, a lower-layer protocol control unit that is unused and has not failed is selected, and further, the disk device selection means applies the disk to the drive switching circuit that is installed in the lower-layer protocol control unit selected by the effective lower-protocol control unit selection means. In order to control the selection of the disk device according to the device number, even if a failure occurs in the lower protocol control unit, the disk device attached to the failed lower protocol control unit via another lower protocol control unit Data transfer can be performed, and as a result, it is possible to improve system performance by using an excellent data transfer method that has never been used before. It is possible to provide a click device connection device.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of an embodiment of the present invention.

FIG. 2 is a block diagram showing details of a bus connection control circuit shown in FIG.

FIG. 3 is a block diagram showing an example of a conventional connection system between a magnetic disk device and a host device.

[Explanation of symbols]

1a to 1d Bus connection control circuit 2a to 2d SCSI drive device (disk device) 3a to 3d Upper SCSI bus 4a to 4b Lower SCSI bus 9 Disk device connection device 10a to 10d Upper device 11 Upper SCSI protocol controller (upper protocol control unit) 12a to 12d Lower SCSI protocol controller (lower protocol control unit) 13A Upper SCSI lower SCSI control circuit 13B Drive switching control circuit 14 Lower SCSI switching circuit 15 Data line 16 Upper SCSI control line 17 Lower SCSI control line 18 Lower SCSI switching control line 19 Drive switching control lines 41a to 41d Lower SCSI bus 42a to 42d Lower SCSI bus 50 Disk device switching control unit 51a to 51d Drive switching circuit

Claims (3)

[Claims] 1. A high-order protocol control unit for controlling data transfer with a high-order device, and a plurality of low-order protocol control units for controlling data transfer with a plurality of disk devices, respectively.
In a magnetic disk device connection device including a disk device switching control unit that controls connection with the plurality of disk devices based on a disk device number designated by a host device, the plurality of lower protocol control units includes the protocol A drive switching circuit that connects the control unit and the plurality of disk devices is provided together, and the disk device switching control unit selects one of the plurality of lower protocol control units when a disk device number is designated by the higher-level device. The effective lower protocol control unit selecting means for selecting a lower protocol control unit that is unused and not in failure, and the drive switching circuit provided in the lower protocol control unit selected by the effective lower protocol control unit selecting unit. Disk that controls to select the disk device according to the disk device number Disk device connection apparatus characterized by comprising a preselection unit. 2. A usage status storage unit for storing the plurality of usage statuses and error output statuses as lower protocol control unit information, and the lower level protocol control unit stored in the usage status storage unit. 2. The disk device connection device according to claim 1, further comprising: lower protocol control unit information reference means for selecting the lower protocol control unit based on information. 3. The disk device switching control unit, when a disk device number is specified by the higher-level device, transfers the data according to the specification. 2. The disk device connection device according to claim 1, further comprising error lower protocol control unit avoiding means for selecting a lower protocol control unit.