JPH08221215A - External storage controller - Google Patents

Abstract

PURPOSE: To prevent a fault when a bank is degraded by notifying a memory use part of the state of the bank by a memory control part when either one of banks is degraded. CONSTITUTION: An external storage controller 20 is provided with plural banks where a cache memory 26, control information storage parts 27a and 27b and an involatile memory 28 are divided by the different areas of supply power sources 4a and 4b, and a memory control part (cache control part) 24 performing the control of a memory. By simultaneously writing information in the different banks, the duplex of the memory is performed. When either one of the banks is degraded, the memory control part 24 notifies a memory use part (channel adapter) 21 using the memory of the usable banks. As a result, the memory use part 21 performs an update processing by only the normal banks. Therefore, the writing in the degraded banks can be prevented and the generation of a writing error can be prevented.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an external storage control device having a high-speed write function for notifying a host of a normal end by writing user data in a cache without synchronizing with an external storage device.

[0002]

2. Description of the Related Art A conventional external storage control device realizes a high-speed writing function by providing a nonvolatile memory and separating power supply. Then, in the external storage control device, in order to prevent data loss when the power is cut off, the user data is written to both the cache memory and the non-volatile memory at the same time, and the validity of the user data such as the content of the data and the starting place is verified. The control information shown is important because it writes back the data on the non-volatile memory to the external storage device, and so on.
Duplication is planned.

Hereinafter, memory spaces having the same power supply will be referred to as banks, and therefore memory spaces having different power supplies will have different banks. This duplication of control information takes into consideration the ease of management and the ease of trouble-shooting. For example, by adding a fixed value to one address, the other address can be obtained by simply finding one address. Is taking

When one bank is degenerated for some reason (failure or power supply is down), an error occurs when writing to both banks at the same time without noticing it.

[0005]

In the above-described conventional control information duplication, when one bank is degenerated for some reason, if writing is performed to both banks at the same time without noticing it. An error occurs. As a result, the external storage device may be unusable because it is separated from the host device.

According to the present invention, a cache management unit that manages cache resources (resources), which is a memory unit, constantly manages the state of the bank and notifies the module that updates the control information of the state. The purpose is to prevent obstacles during degeneration.

[0007]

FIG. 1 is a diagram for explaining the principle of the present invention. In FIG. 1, 1 is a host device, 4a and 4b are power supplies, 20 is an external storage controller, 21 is a channel adapter, and 22 Is a device adapter, 24 is a memory management unit (cache management unit), 26 is a cache memory, 27a,
27b is a control information storage unit, 28 is a non-volatile memory (NV
S) and 30 are external storage devices.

The present invention has the following structure in order to solve the problems of the conventional example. (1) Power supply 4 for memories 26, 27a, 27b, 28
In an external storage control device 20 that includes a plurality of banks divided in different areas a and 4b and a memory management unit 24 that manages the memory, one of the banks is degenerated. If the memory management unit 24 uses the memory, the memory management unit 24
Notify the state of the bank.

(2) Memories 26, 27a, 27b, 28
In an external storage control device having a plurality of banks divided into different areas of the power supply 4a, 4b and a cache management unit 24 for managing the memory, and for duplicating the control information storage units 27a, 27b. If any of the above is degenerated, the cache management unit 24 notifies the channel adapter that uses the memory of the state of the bank.

[0010]

The operation of the present invention based on the above configuration will be described. In the external storage control device 20 for duplicating by simultaneously writing information in different banks, if any of the banks is degenerate, the memory management unit 24
Notifies the usable bank to the memory use unit 21 that uses the memory. As a result, the memory use unit 21
Performs update processing only on normal banks. Therefore, it is possible to prevent a write error from occurring.

In addition, the external storage control device 20 has a control information storage section 27a and a control information storage section 27 which are different banks.
In the duplication by simultaneously writing control information to b, if any of the banks is degenerated, the cache management unit 24 notifies the channel adapter 21 that uses the memory of the available bank. As a result, the channel adapter 21 can update the control information only in a normal bank, and can prevent a control information write error even when the bank is degenerated.

[0012]

2 and 3 are views showing an embodiment of the present invention, and an embodiment will be described below with reference to the drawings.

§1: Description of External Magnetic Disk Controller FIG. 2 is an explanatory diagram of the external magnetic disk controller. Figure 2
In FIG. 1, the host device (host) 1 has a plurality of channels and reads / writes data from / to the magnetic disk device 3 via the external magnetic disk control device 2.

The magnetic disk control device 2 has a plurality of modules inside and controls data transfer between the host device 1 and the external magnetic disk device 3. The external magnetic disk device 3 is an external storage device (DASD).

The external magnetic disk controller 2 includes channel adapters (CA) 21a, 2 which are a plurality of modules.
1b, device adapters (DA) 22a and 22b, service adapters (SA) 23a and 23b, cache management unit (CFE: cache function engine) 2
4, resource management unit (RM: resource manager) 25, cache memories 26a and 26b, control information storage unit 27
a, 27b, non-volatile memory (NVS) 28a, 28
b, hard disks 29a, 29b are provided.

The external magnetic disk control device 2 has a group 0 and a group 1 for duplication, and has a cache management unit 24, a resource management unit 25, and a memory (cache memories 26a and 26b, control information storage units 27a and 27b, The non-volatile memories 28a and 28b) are common to each group.

Within each group, a bus (BUS) for connecting modules and a system bus (S-BUS) used for command transfer for maintenance are provided. The channel adapters 21a and 21b are modules that receive data from the respective channels of the higher-level device 1, write it in the memory, and update the control information.

The device adapters 22a and 22b are modules for transferring data between the external magnetic disk device 3 and the memory. The service adapters 23a and 23b are
A maintenance adapter that detects and manages degeneration of resources such as memory.

The cache management unit 24 is a module that manages the cache memories 26a and 26b, the non-volatile memories 28a and 28b, the control information storage units 27a and 27b, and notifies these addresses to the channel adapters 21a and 21b.

The resource management unit 25 is a module for managing resources of the entire external magnetic disk control device 2. The cache memories 26a and 26b are volatile memories in which data is lost when the power is cut off, and high-speed processing can be performed by updating the data in this cache memory.
Then, the cache memory 26a is the power supply (1) in the normal state.
Power is supplied from 4a, and cache memory 26b
Is being supplied with power from the power source (2) 4b.

The control information storage units 27a and 27b are non-volatile memories that are battery-backed up memories for storing control information, and the control information storage unit 27a.
Is normally supplied with power from the power supply (1), and the control information storage unit 27b is supplied with power from the power supply (2). The control information to be duplicated is stored in the control information storage unit 2
The address of the control information storage unit 27b can be obtained by adding a certain value to the address of 7a.

The non-volatile memories 28a and 28b are battery-backed memories, and the non-volatile memory 2
8a is supplied with power from the power supply (1), and the nonvolatile memory 28b is supplied with power from the power supply (2).

The hard disks 29a and 29b store information used for starting up the service adapters 23a and 23b, respectively. Power supply 4a, 4b
Are different normal power sources, and power source (1)
Is a cache memory 26a, a control information storage unit 27a,
Power is supplied to the nonvolatile memory 28a, and the power source (2) is
Power is supplied to the cache memory 26b, the control information storage unit 27b, and the non-volatile memory 28b. Therefore, this memory has two banks. In the memory of FIG. 2, the right side is bank 1 and the left side is bank 0.

The SSP is a port used when accessing the memory. §2: Description of high-speed write function The external magnetic disk controller 2 needs to increase the processing speed when reading / writing data from / to the external magnetic disk device 3. Therefore, the external magnetic disk controller 2
There is a high-speed write method in which data is simultaneously written in the cache memories 26a, 26b and the non-volatile memories 28a, 28b to notify the higher-level device 1 of normal termination.

In such a high-speed writing function, the user data is stored in the cache memory 26a or 26b and the non-volatile memory 28a in order to prevent data loss when the power is cut off.
Alternatively, the control information that is written in the control information storage unit 27a and the control information storage unit 27b that are non-volatile memories with different power supplies (different banks) are written to the control information storage unit 27b at the same time. By being written, duplication is achieved.

When one bank is degenerated for some reason, notification is made by inter-module communication so as not to write to both banks at the same time. The operation of high speed writing will be described below with reference to FIG.

1) High-speed write flow when bank is normal FIG. 3A is a flow when bank is normal. Less than,
The flow when the bank is normal will be described according to the numbers in FIG.

One channel adapter (CA) 21a
Accepts a user data write request from the host device 1. The channel adapter 21a which has received the user data write request receives the cache memories 26a, 26 for performing high-speed writing to the cache management unit (CFE) 24.
b, non-volatile memory 28a, 28b, control information storage unit 2
Request addresses 7a and 27b.

The cache management unit 24 which has received the address request for performing the high speed writing notifies the channel adapter 21a of the requested address. At this time, since the memory section is normal, it is also notified that both bank 0 and bank 1 can be used.

The channel adapter 21a, which has received the notification from the cache management unit 24, processes the user data at high speed by simultaneously writing the user data in the cache memory 26a and the non-volatile memory 28a.

Further, the channel adapter 21a is
The control information is written to both bank 0 and bank 1 (control information storage units 27a and 27b). The channel adapter 21a notifies the higher-level device 1 of normal termination.

The external magnetic disk device 3 is written by the device adapter 22a from the non-volatile memory 28a. 2) High-speed write flow when bank degeneracy occurs FIG. 3B is a flow when a bank degeneracy occurs. Hereinafter, the flow when the degeneration of the bank 1 occurs will be described according to the numbers 1 to 3 in FIG.

When the bank 1 is degenerated, the degeneration is notified to the service adapters (SA) 23a and 23b through the system bus (S-BUS). The degeneracy of the bank 1 is performed by the service adapter 23a or 23.
b is notified to the cache management unit 24.

One channel adapter 21a receives a user data write request from the host device 1. The channel adapter 21a that has received the user data write request receives cache management memories 26a and 26b for performing high-speed writing to the cache management unit 24, nonvolatile memories 28a and 28b, control information storage units 27a and 2a.
Request address 7b.

The cache management unit 24 which has received the address request for performing the high-speed writing notifies the channel adapter 21a of the requested address. At the same time, it notifies that only bank 0 can be used.

The channel adapter 21a, which has received the notification from the cache management unit 24, processes the user data in the cache memory 26a and the non-volatile memory 28a at the same time by high-speed writing.

Further, the channel adapter 21a is
The control information is updated only in the control information storage unit 27a of bank 0. The channel adapter 21a notifies the higher-level device 1 of normal termination.

The external magnetic disk device 3 is written by the device adapter 22a from the non-volatile memory 28a. Further, although the external magnetic disk control device has been described in the above embodiment, the present invention is not limited to this, and the present invention can be applied to an external storage control device such as an optical disk or a magnetic tape. Further, the user data can be written in different banks.

[0039]

As described above, the present invention has the following effects. (1) If any of the different banks are degenerate,
Since the state of the bank is notified to the module that uses the memory, it is possible to prevent writing to the degenerated bank and prevent the occurrence of a write error.

(2) When one of the different banks is degenerated, the cache management unit 24 notifies the channel adapter 21 that uses the memory of the state of the bank. It is possible to prevent the control information from being written, and it is possible to prevent the occurrence of the control information write error even when the bank is degenerated while maintaining the high-speed write control method.

[Brief description of drawings]

FIG. 1 is a diagram illustrating the principle of the present invention.

FIG. 2 is an explanatory diagram of an external magnetic disk control device according to an embodiment.

FIG. 3 is an explanatory diagram of a high speed write operation according to an embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Host device 4a, 4b Power supply 21 Channel adapter 22 Device adapter 24 Memory management unit (cache management unit) 26 Cache memory 27a, 27b Control information storage unit 28 Nonvolatile memory 30 External storage device

Claims (2)

[Claims] 1. An external storage controller for duplicating the memory, comprising: a plurality of banks in which the memory is divided into areas of different power supplies; and a memory management unit for managing the memory. Is degenerate, the memory management unit notifies the memory use unit that uses the memory of the state of the bank. 2. An external storage controller for duplicating control information of the memory, comprising: a plurality of banks in which the memory is divided into areas of different power supplies; and a cache management unit for managing the memory. If any of the above is degenerate, the cache management unit notifies the channel adapter that uses the memory of the state of the bank.