JP2781119B2 - Redundant system - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a duplex system, and more particularly to a duplex system in which an auxiliary storage device is duplexed in a plurality of duplex units.

[0002] From the viewpoint of improving reliability and promptly responding to a failure, various duplex systems have been realized. Among them, the auxiliary storage device is also duplicated.

[0003]

2. Description of the Related Art FIG. 9 shows a conventional technique, and particularly shows a method of duplicating an auxiliary storage device in a conventional duplex system.

FIG. 9A shows a system in which the "entire" auxiliary storage device is adopted as a unit of duplication to achieve duplication. In this case, for each of the auxiliary storage devices (hereinafter, referred to as main device) 52 as the main device, an auxiliary storage device (hereinafter, referred to as sub-device) 53 which is the exact same slave device is prepared. Each of the main devices 52 and each of the slave devices 53 physically correspond one-to-one.

[0005] Each data is stored in the main device 52 and the slave device 53 at a position where a physical address (and a logical address) is equal. Therefore, for the main unit 51,
An identical system of the main device 52 and a system of the slave device 53 are connected. That is, this is an example of physical duplication.

FIG. 9B shows a system in which a "volume" of an auxiliary storage device is adopted as a unit of duplication to achieve duplication. In this case, for each of the volumes of the main device 52, the same volume is stored in one of the slave devices 53. The main device 52 and the slave device 53 do not physically correspond to each other.

[0007] Each data is stored in the main device 52 and the slave device 53 at positions where the logical addresses are equal (the physical addresses are different). Therefore, the system of the main unit 52 and the system of the slave unit 53 are connected to the main unit 51, and the position of the volume of the slave unit 53 corresponding to the volume of the main unit 52 is not the physical position. Irrelevant. That is, this is an example of logical duplication.

[0008]

The duplex system shown in FIG. 9 (A) in which the whole of the auxiliary storage device is a unit is easy to maintain. For example, the master device 52-1 or the slave device 5
If a failure occurs in any of 3-1, the system can be restored without being conscious of any duplication in the other main device 52-2 or sub device 53-2.

[0009] However, in the case of FIG. 9A, the economic burden at the time of introducing the system is large, and the resource use efficiency is not economical. That is, the auxiliary storage devices (52, 5
3) is always twice as many as the main unit 52. In addition, there are two main units 52, but if it is known that, for example, there is little data to be duplicated, only one slave unit 53 may be used. However, even in such a case, according to the method of FIG. 9A, two slave devices 53 are required, and the utilization efficiency of resources is reduced.

Contrary to this, a duplex system in units of "volumes" of the auxiliary storage device shown in FIG.
The economic burden is small, and the utilization efficiency of resources is also economical.
That is, in the case of the above-described example, only one slave device 53 is required, and the efficiency of resource utilization is high.

However, in the case of FIG. 9B, there is a difficulty in maintenance. For example, when a failure occurs in either the master device 52-1 or the slave device 53-1, the volume of the master device 52-1 and the volume of the slave device 53-2 are duplicated. It is necessary to be aware of the duplication in these. That is, since there is a possibility that the main device 52-1 may have a failure, it is necessary to perform system restoration while being aware of all the duplication relations relating to the main device 52-1.

An object of the present invention is to provide a duplex system in which an auxiliary storage device is duplicated in units of both the whole and the volume.

[0013]

FIG. 1 is a block diagram showing the principle of the present invention, and shows a duplex system according to the present invention. This duplex system includes a main unit 1 of a data processing apparatus, an auxiliary storage unit 2 as one or more main units connected to the main unit 1, and an auxiliary storage unit connected to the main unit 1 and serving as a main unit. And an auxiliary storage device 3 which is one or more slave devices for storing data to be duplicated among the data in the storage device 2.

In this redundant system, an information table 4 for storing redundant information on the auxiliary storage devices 2 and 3 is provided in each of the auxiliary storage device 2 as a main device and the auxiliary storage device 3 as a slave device. Information table 4
Is provided with a status display section 5 that indicates whether the auxiliary storage devices 2 and 3 are in a physical or logical duplex state.

Data indicating the physical duplication is stored in each of the status display sections 5 of the information table 4 of the auxiliary storage device 2-1 which is a physically duplicated main device and the auxiliary storage device 3-1 which is a subordinate device. You. Each of the status display units 5 of the information table 4 of the auxiliary storage devices 2-2 and 2-3 as the logically duplicated main devices and the auxiliary storage device 3-2 as the subordinate device is provided.
Data indicating logical duplication is stored.

[0016]

An auxiliary storage device (hereinafter, referred to as a main device) 2-1 as a main device and an auxiliary storage device (hereinafter, referred to as a slave device) 3-1 as a slave device are mutually connected in units of the entire auxiliary storage device. It is duplicated. That is, it is physically duplicated. Therefore, data indicating this is stored in the status display section 5 of the information table 4.

The master devices 2-2 and 2-3 and the slave device 3-2 are duplicated in units of volumes of the auxiliary storage device. That is, it is logically duplicated. Therefore, the data indicating this is displayed in the status display section 5 of the information table 4.
Is stored in

The main unit 1 performs processing for the main unit 2 and the slave unit 3 according to the contents of the status display unit 5. For example, the main unit 2-1 in which the status display unit 5 indicates “physical duplication”
The read / write for the slave device 3-1 is performed for the same access position. Further, the state of the duplexing is changed by changing the content of the status display section 5 from “physical duplexing” to “logical duplexing” or vice versa.

According to the above, both physical duplication using the entire auxiliary storage device as a unit of duplication and logical duplication using the volume of the auxiliary storage device as a duplication unit are mixed.
Can manage (can support both). This has the advantage of easy maintenance of physical duplication,
A duplex system can be obtained that simultaneously realizes both the economics of logical duplexing and the advantage of efficient resource utilization.

That is, when a failure occurs in one of the main unit 2-1 and the subordinate unit 3-1, the system can be restored without being aware of other duplicated relationships.

Since the main units 2-2 and 2-3 use a volume as a unit of duplication, the duplication of these two (plural) main units can be performed by one unit (or a smaller number than the main unit). It is economical and can increase the efficiency of resource use.

[0022]

FIG. 2 is a block diagram of an embodiment, and shows a duplex system, particularly a duplex system in which the auxiliary storage device is duplicated. In accordance with the present invention, this duplex system comprises a physically duplicated master device 2-1 and slave device 3-1 and a logically duplicated master device 2-2, 2-3, and slave device 3-2.
3-3.

The main unit 1 is composed of a processing unit including a CPU (central processing unit) and a main storage unit, and has an input / output unit. The duplication state transition processing unit 6, the read / write processing unit 7, and the table creation processing unit 8 are each realized by a CPU and a program corresponding to each existing in the main storage device. The main storage information table 9 exists on the main storage device.

The duplicated state transition processing unit 6 includes all the main units 2
The information table 4 is managed for all the slave devices 3 (auxiliary storage devices). That is, by managing information (duplication information) for managing the state of duplication,
The duplication of the auxiliary storage device (2, 3) is managed.

For example, when the operator instructs physical duplication of the main unit 2-1 from the input / output device, necessary processing such as changing the contents of the information table 4 of the main unit 2-1 is performed in response to the instruction. Further, for example, if the main unit 2-2 and the subordinate unit 3-2 are separated at the time of occurrence of a failure and the state is changed so as not to be duplicated, the contents of the information table 4 are changed accordingly. Perform necessary processing.
That is, when the state of duplication of the auxiliary storage device (2, 3) changes, the content of the corresponding information table 4 is changed accordingly.

The read / write processing unit 7 receives the request from the operating system (OS) when the input / output to the auxiliary storage device (2, 3) is required,
The input / output processing is performed. When the data to be accessed is duplicated, this input / output (read / write) process is performed for both the main device 2 and the slave device 3 where the data exists.

Therefore, the read / write processing unit 7 needs to know the duplex state of the data to be accessed. Therefore,
Each time the read / write processing unit 7 sets the auxiliary storage device (2,
3) In the main storage device, the information table 9 in the main storage is provided so that the duplicated information can be obtained without referring to the information table 4 in 3).
Is provided. The main storage information table 9 is created by the table creation processing unit 8.

The table creation processing unit 8 is started, for example, at the start-up of the duplex system, reads the contents of the information tables 4 of all the main units 2 and all the sub units 3, and uses them to execute a predetermined operation. By performing the processing, the in-main-memory information table 9 is created. Therefore, the main memory information table 9 stores all the duplicated information.

Which of the main unit 2 and the slave unit 3 is to be physically duplexed or logically duplexed is instructed by an operator's input from the input / output device of the main unit 1. The same applies to a duplex partner device. However, in the case of logical duplication, the volume of the main device 2 to be associated with which volume of the slave device 3 is determined by the operating system of the main device 1 according to the empty state of the volume of the slave device 3 and the like.

In this embodiment, when the physical duplication and the logical duplication are mixed, the main unit 2-1 to be physically duplicated is used.
The slave device 3-1 is provided on the side closer to the main device 1. However, the operator can determine the arrangement position and the correspondence.

FIG. 3 shows an example of the information table 4. FIG.
(A) and (B) show the information tables 4 of the main units 2-1 and 2-2, respectively. The information table 4 indicates, for each volume in the auxiliary storage device (2, 3), the duplex status of the volume in correspondence with the volume number. The volume number is uniquely determined for each volume in the volume. Volume number is "1"
To “X” (X is a positive integer). As shown in the figure, the information table 4 stores “duplication status” and “other device (name, etc.)” of the volume in correspondence with the volume number.

Here, the entry of the predetermined volume number n is used as the status display section 5. “N” is a volume number that does not actually exist (is impossible) in the auxiliary storage device (2, 3). In this embodiment, n = 0.

The volume number 0 (entry) is used as the status display unit 5 and the auxiliary storage device (2, 3)
The "redundancy status" and "other device" are stored. The volume number 0 may be considered to mean the entire auxiliary storage device (2, 3).

In FIG. 3A, the volume number 0 of the main unit 2-1 is "physical duplication". This instruction input is performed by the operator. That is, when the operator instructs the main apparatus 2-1 to "duplicate" the volume 0, the processing is processed as an instruction to duplicate the entire main apparatus 2-1 and the physical duplication is executed.

At this time, the "partner device" is not necessarily the slave device 3-1 having the same physical address, but can be selected by the operator as appropriate. Also, the main unit 2-1
, X correspond to the volumes 1, 2,... X of the slave device 3-1. Since this is also physical duplication, it is predetermined. From the above, in each volume number (entry) other than volume number 0, the storage of the “duplication status” and the “other device” is omitted.

In FIG. 3B, the volume number 0 of the main unit 2-2 is "logically duplicated". In this case, the operator has not yet input an instruction to “duplicate” the volume number 0 for the main device 2-2.
Therefore, the volume number 0 is kept in its initial state, that is, a state indicating “logical duplication”. The main device 2-2 is a target of logical duplication, and therefore, "───" indicates that there is no "partner device" corresponding to the entire main device 2-2.

For example, for the volume number 1, the duplication state is "not duplicated (duplication unnecessary)", and therefore, there is no "partner device". The state of duplication is instructed by the operator or is determined in advance by the type of data. As for the volume number X-1, the duplex state is "duplex", and the "other device" is the volume number X-1 of the slave device 3-2. That is, as shown in FIG. 2, logical duplication is performed for each volume.

As can be seen from the above, the duplex system of this embodiment supports both physical duplex and logical duplex, but basically employs logical duplex. Therefore, the change of the duplication state is performed for each volume. However, when the duplication of a certain volume number n = 0 is designated, this is used as a trigger, and thereafter, the master device 2 and the corresponding slave device 3 are brought into a physical duplication state. The release of the state of the physical duplication is performed by instructing the logical duplication of the volume number n = 0. As a result, the operator can freely set either the physical duplication or the logical duplication.

Although FIG. 3 shows the information table 4 of the main device 2, the information table 4 of the slave device 3 has substantially the same configuration. For example, the information table 4 of the slave device 3-1
Is the same as that in the information table 4 of the main device 2-1 in FIG. The information table 4 of the slave device 3-2 is shown in FIG.
In the information table 4 of the main device 2-2 in (B), the “partner device” of the volume number (X-1) is changed to the “main device 2-2”.
Volume number (X-1). "
"Duplex state" is "non-redundant" and "other device" is "───".

FIG. 4 shows an example of the information table 9 in the main memory. The main memory information table 9 includes a plurality of pages 91, 92,
Consists of ... Each page 91, 92,... Corresponds to each of the information tables 4 of all the main units 2 and all the sub units 3. For example, the page 91 corresponds to the information table 4 (FIG. 3A) of the main device 2-1, and is created based on this. The page 92 corresponds to the information table 4 (FIG. 3B) of the main device 2-2.

The page 91 specifies the volume number of the slave device 3-1 corresponding to each volume number of the main device 2-1 by writing it in the column of "partner device". This writing is performed by the table creation processing unit 8 as described above.
The configuration other than the “other device” is the same as that of the information table 4 in FIG.

The identification of the "partner device" is performed by the main device 2-1.
Is performed by utilizing the fact that is physically duplicated. That is, in order to make the physical address the same, the partner device of the duplexing of the main device 2-1 is the slave device 3-1 and the volume number corresponding to the volume number 1 is also "1".

The structure of the page 92 is the same as that of the information table 4 shown in FIG. This is because the information table 4 in FIG. 3B is for the case of logical duplication, and the necessary data has already been stored for each volume.

In the pages 91, 92,..., The volume number 0 (entry) is used as an area 5 ′ corresponding to the status display section 5 in the information table 4. By referring to the area 5 ', the auxiliary storage devices 2, 3
Is in a state of physical duplication or logical duplication.

Next, the management of the duplicated information and the duplication and access of the master unit 2 and the slave unit 3 based on this will be described with reference to the respective processing flows of FIGS. 5 to 7 and FIG.
FIG. 5 is a flowchart of a process of creating the main storage information table 9 executed by the table creation processing unit 8.

In FIG. 5A, a volume number (parameter) V = 0 is set as an initial setting (S1). The information table 4 of the auxiliary storage device number n to be processed is read into a predetermined position of the main storage information table 9 (S
2) For example, the page of the number n is set. The auxiliary storage device number n is uniquely determined in the system without distinction between the main device 2 and the slave device 3.

In the information table 4 read in S2, the information table 4 of the master device 2 or the slave device 3 described in the "other device" corresponding to the volume number V is read (S3). At this time, if up to the volume number is specified as the “other device”, only the entry of the volume number in the information table 4 needs to be read.

In the information table 4 read in S2, it is checked whether the "duplication status" corresponding to the volume number 0 is "physical duplication" (S4). If not physical duplication (logical duplication), the processing A shown in FIG. 5B is executed (S5). That is, a subroutine for executing the process A is called. This subroutine sets the duplex information of the volume number V in the information table 4 read in S2 and made one page of the information table 9 in the main memory. Specifically, the column of “partner device” of the entry of the volume number V is described in a form that specifies up to the volume number of the partner device.

As post-processing, the volume number V is incremented by +1 (S6). It is checked whether or not the processed volume number V is the last volume number in the information table 4 read in S2 (S7).

If it is the last volume number, the process ends. If it is not the last volume number, S3 and subsequent steps are repeated with the new V value counted up in S6.

In S4, if physical duplication is performed, the volume number V is sequentially changed from 1 to X (the last volume number) by +1 at a time, and the process A is executed each time (S8).

The duplication information of the partner device obtained in S3 is used when setting the duplication information in S5 or process A.
It is used for confirming the information to be set. As described above, the main memory information table 9 is created when the system is started.

This will be described with reference to FIG. 8 for the case of physical duplication and logical duplication of FIG. Note that the processing flow of FIG. 5 corresponds to the processing indicated by in FIG. Assuming that the auxiliary storage device number n is “2-1”, FIG.
The information table 4 of (A) is read, and since it is determined in S4 that physical duplication has been performed, S8 is executed. At S8,
The page 91 (page 2-1) shown in FIG. 4 is created based on the fact that the partner device is the slave device 3-1 and that the volume number of the partner is equal to its own volume number because of the physical duplication. You. In S3 or S8, the slave device 3
Since the “partner device” in the entry of the volume number 0 of −1 is “main device 2-1”, it is confirmed that the duplex information is correct.

Assuming that the auxiliary storage device number n is "2-2", the information table 4 of FIG. 3B is read in S2 and the logical duplication is found in S4, so that S3 to S7 are repeated. Page 92 shown in FIG.
2) is created. In the process A, the content of the information table 4 read in S2 is set as it is as the content of the “partner device”.

FIG. 6 is a flow chart of the updating process of the information table 4 and the main memory information table 9 executed by the duplex state transition processing unit 6. The duplication state transition processing unit 6 is started when a new duplication instruction is issued by the operator, or when one of the duplicated auxiliary storage devices (2, 3) is disconnected when a failure occurs.

In FIG. 6A, it is checked whether or not the volume number V of the volume that has undergone some transition in the duplex state is "0" (S9). If it is not "0", the processing B shown in FIG. 6B is executed for the volume (S10). That is, a subroutine for executing the process B is called. This subroutine is performed by using the information table 4 of the master device 2 and / or the slave device 3 in which the volume exists.
The contents of the entry of the volume number V (duplication information, that is, the contents of “duplication state” and “partner device”) are updated for the page of the information table 9 in the main memory corresponding to the information table 4.

This update is performed, for example, as necessary, by using a page corresponding to the information table 4 of the main device 2, the information table of the slave device 3, and the information table 4 of the main device 2 of the information table 9 in the main memory. Are executed in the order of pages corresponding to the information table 4 of the slave device 3 in the information table 9 in the main memory.

If it is "0" in S9, the volume number V is changed in order from 1 to X (the last volume number) by +1 and the process B is executed each time (S1).
1). As a result, the duplication state of the entire auxiliary storage device (2, 3) and the duplication information of the whole are changed as a series of processing.

The above is described with reference to FIG. 8 for the case of FIG. Note that the processing flow in FIG. 6 corresponds to the processing indicated by in FIG. For example, if a failure occurs in the slave device 3-2, it is necessary to eliminate the duplication relationship. In this case, for example, the main memory information table 9
The volume number (X-1) of the main unit 2-2 and the volume number (X-
Regarding 1), the fact that there is a change in the duplication status and the contents thereof are notified.

First, for the main unit 2-2, since the volume number V = (X-1) in S9, S10 or process B is executed. As a result, the entry of the volume number (X-1) of the information table 4 of the master device 2-2 and the entry of the volume number (X-1) of the information table 4 of the slave device 3-2 are changed. The corresponding entry of the corresponding page in the table 9 is changed.

FIG. 7 is an access processing flow for the auxiliary storage devices (2, 3) executed by the read / write processing unit 7. The read / write processing unit 7 includes an auxiliary storage device (2,
When the access in 3) is required, a predetermined access is performed in response to a request from the operating system to that effect.

In FIG. 7, it is checked whether or not the access target volume is duplicated by referring to the entry of the corresponding volume of the corresponding page in the main storage information table 9 (S12).

If it is not duplicated, normal access processing, that is, processing for accessing the access target volume is performed (S13). If it is duplicated, it is checked whether the "duplication status" of the volume number 0 (area 5 ') is "physical duplication" in the relevant page where the access target volume exists (S14).

If not "physical duplication" (logical duplication), the access position (physical address) of the volume in the slave device 3 is determined (S15). This physical address can be obtained based on the corresponding volume number in the slave device 3 indicated in the "partner device" of the entry.

In the case of “physical duplication”, S15 is omitted. Access to both the main device 2 and the slave device 3 (S
16). The above is described with reference to FIG. Note that the processing flow of FIG. 7 corresponds to the processing indicated by in FIG.

For example, when accessing the volume 1 of the main unit 2-2, since it is "not duplicated" with reference to the page 92 of FIG. 4 in S12, access is executed only to this volume in S13.

When accessing the volume X of the main unit 2-2, since it is "duplication" but not "physical duplication", the physical address of the volume 1 of the slave unit 3-1 is obtained in S15. Then, in S16, the main device 2-
Access is performed to both the volume X of the secondary device 2 and the volume 1 of the slave device 3-3.

Further, when accessing the volume 1 of the main unit 2-1, since it is "physical duplication", S15 is omitted, and the volume 1 of the main unit 2-1 and the volume 1 of the subordinate unit 3-1 are skipped in S16. Access is performed to both.

As described above, by referring to the information table 9 in the main memory, even if physical duplexing and logical duplexing are mixed, access is possible without particularly complicated processing. In addition, when the system is started up and the duplex state is changed, the duplexed data can always be accessed accurately by creating and changing the information table 9 in the main memory.

[0070]

As described above, according to the present invention,
In a duplex system in which auxiliary storage devices are duplicated, by storing data indicating the duplex status of the auxiliary storage device in an entry of a predetermined volume number in an information table, both physical duplication and logical duplication can be performed in one system. Simultaneous realization makes it possible to construct a duplex system that is easy to maintain, economical, and efficient in resource utilization.

[Brief description of the drawings]

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

FIG. 2 is a configuration diagram of an embodiment.

FIG. 3 is an explanatory diagram of an information table.

FIG. 4 is an explanatory diagram of a main memory information table.

FIG. 5 is a flowchart of a main memory information table creation process.

FIG. 6 is a flow of a duplex information updating process.

FIG. 7 is an access processing flow.

FIG. 8 is an explanatory diagram of duplication.

FIG. 9 is an explanatory diagram of a conventional technique.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Main apparatus 2 Auxiliary storage device (main device) as a main device 3 Auxiliary storage device (slave device) as a subordinate device 4 Information table 5 Status display unit 6 Duplex state transition processing unit 7 Read / write processing unit 8 Table creation processing unit 9 Main memory information table

Claims (5)

(57) [Claims] 1. A main unit (1) of a data processing device, an auxiliary storage device (2) as one or more main units connected to the main unit (1), and a main unit (1). A redundant system, comprising: one or two or more auxiliary storage devices (3), which are connected and store data to be duplicated among the data in the auxiliary storage device (2) as the main device; Each of the auxiliary storage device (2) as a main device and the auxiliary storage device (3) as a slave device has the auxiliary storage device (2, 2).
There is provided an information table (4) for storing the duplex information of 3), and in each of the information tables (4), the auxiliary storage device (2, 3) is in a duplex state of either physical duplex or logical duplex. A status display unit (5) is provided to indicate whether the auxiliary storage device (2--
1) and data indicating physical duplication are stored in each of the status display sections (5) of the information table (4) of the auxiliary storage device (3-1) as a slave device, and the master device is a logically duplicated main device. Auxiliary storage device (2-
2, 2-3) and an auxiliary storage device as a slave device (3-2)
A data indicating logical duplication is stored in each of the status display sections (5) of the information table (4). 2. The information table (4) is a table showing a duplication state of the volume corresponding to a volume number of the auxiliary storage device (2, 3). 2. The duplex system according to claim 1, wherein the duplex status of the auxiliary storage device (2, 3) is indicated corresponding to a predetermined volume number. 3. A read / write processing unit (7) for performing read / write processing of the auxiliary storage device (2, 3), and a read / write processing unit (7) created based on each information table (4) of the auxiliary storage device (2, 3). ., Each of the pages (91, 92,...) Corresponding to the information table (4), and an area (5 ′) corresponding to the status display section (5) on each of the pages (91, 92,...). The main storage device (1) is provided with an information table (9) in the main memory, and the read / write processing unit (7) is configured to access the auxiliary storage device (2, 3) prior to reading / writing. hand,
3. The method according to claim 1, wherein the content of the area is referred to and a predetermined process is performed according to the content.
The duplex system according to any one of the above. 4. The duplication of said auxiliary storage device (2, 3).
When the status changes, the duplex information is changed accordingly
State transition processing unit (6) for performing
Provided in (1), The duplication state transition processing unit (6) responds to the change.
Information table (4) and information table in main memory
Change the contents of (9) Claim 1 or Claim
The duplex system according to claim 2. 5. When the duplex status transition processing unit (6) is instructed to duplicate a predetermined volume number as the status display unit (5), the physical status of the auxiliary storage device (2, 3) is changed. 5. The duplex system according to claim 4, wherein a predetermined process for duplexing is executed for the information table (4) and the main memory information table (9).