JPH10224378A - Client server system and its control method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable a standby server to receive the physical address of LAN of a main server by receiving and transmitting a packet that is addressed to the main server by means of the physical address used in the LAN when a communication device of the standby server substitutes for the communication processing of the main server having a failure. SOLUTION: A communication management part 4 detects the failure of a main server 1 to set a failure state of its own server and notifies a communication management part 13 of a standby server 10 of the failure of the server 1 via a communication link 20. Then the part 4 sends the data to be sent to a LAN 21 which are received from a server process 7, etc., to the part 13 via the link 20 and also sends the reception data received from the part 13 to the process 7. Receiving the notification of failure from the server 1, the part 13 changes the setting so as to make a LAN interface 11 receive the packet addressed to a physical address of a LAN interface 2 by means of a LAN driver 12.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for controlling a client server system and a client server system related to a system in which a communication device of one computer is replaced by a communication device of another computer in a LAN (local area network) environment. The present invention relates to a packet filter device, a communication method switching method, and a computer-readable recording medium storing program information of the method.

[0002]

2. Description of the Related Art In conventional technologies such as a computer cluster and a hot standby, when a failure occurs in a certain computer and the processing cannot be continued, an alternative computer takes over the processing.

There are various types of clusters,
As an example, takeover of cluster processing will be described with reference to FIG. Primary server 101 and standby server 1
10 and a cluster control SW (software) for taking over the processing is operating. Normally, each server performs a different process. The cluster control SW uses the control communication link 120 to periodically check whether the other party is operating properly.

When a failure occurs in the primary server 101 and the cluster control SW of the primary server 101 detects the failure,
The main server 101 stops the processing and the standby server 110
Is notified to the cluster control SW. Alternatively, the cluster control SW of the standby server 110 periodically changes the
Is detected, a failure of the primary server 101 is detected. In any of the above cases, the cluster control SW of the standby server 110 can detect that the main server 101 has stopped processing.

[0005] Next, the standby server 110 starts taking over the processing executed by the main server 101. The process to be taken over needs to be defined in advance. The following two points are required to take over the processing. (1) Prepare an environment in which the same result can be obtained regardless of which computer is executed. For example, if the primary server performs a database service, the standby server must take over the primary file in order to take over the service. It is necessary for the standby server to be able to access even if the standby server has stopped processing. (2) Switching of communication destination When communicating with another computer via the network, the communication partner is switched from the main server to the standby server so that the other computer does not know.

Although a method for realizing the above (1) has been proposed, description thereof will be omitted here. Here (2)
Switching of the communication destination will be described. Primary server 10
The service provided by 1 to other computers exchanges requests and results thereof over a network. Other computers that communicate with the primary server 101 are:
Even if a failure occurs and the main server 101 stops processing, communication continues to be addressed to the main server 101.

In order for the standby server 110 to take over these communications, the standby server 110 receives a packet addressed to the address of the primary server 101 and transmits a packet from the address of the primary server 101. In TCP / IP, I
Use this function because you can have multiple P addresses.

Normally, the standby server 110 receives only its own IP address. After the main server 101 stops processing, the cluster control SW of the standby server 110 sets TCP / IP software so that the IP address of the main server 101 can be received. As a result, the packet of the primary server 101 can be received, and other computers do not need to make changes due to the stop of the primary server 101.

[0009] When the primary server 101 returns, the standby server 110 stops the service that has been taking over, and also stops receiving packets from the primary server 101 for communication. The above technique is disclosed in JP-A-8-212095.
Exists.

[0010]

However, in the above-mentioned prior art, if a communication device for the LAN 121 of the primary server fails, the standby server 110 takes over the communication addressed to the primary server 101. 1
10 is not the physical address of the LAN 121 of the main server 101 but each transport (TCP / IP, NET
For example, there is a problem that a change must be notified so that all the logical addresses are received for each BEUI.

SUMMARY OF THE INVENTION The present invention has been made in consideration of the above circumstances, and solves the above-mentioned problems, and a method of controlling a client-server system in which a standby server can receive a physical address of a LAN of a main server by a standby server. It is an object to provide a system, a packet filter device, a communication method switching method, and a computer-readable recording medium storing program information of the method.

[0012]

[Means for Solving the Problems]

(1) In order to achieve the above object, in the client server system, when a failure occurs in the primary server, when the communication device of the standby server performs the communication process of the primary server instead, A packet addressed to the main server is received and transmitted using a physical address used in a LAN, and when a communication failure occurs in the main server, the communication processing of the main server is performed without being notified to a client. It is characterized in that a standby server is substituted.

(2) According to the present invention, in order to achieve the above object, a main server which processes a request sent from an arbitrary client via a LAN and returns the processing result, and the main server is stopped Alternatively, in a client server system comprising a standby server for transmitting and receiving data to and from a client in place of the main server when a communication device of the main server fails, the client server system is connected to the main server via the LAN. And the standby server are connected by a dedicated communication link to control the LAN interface, a LAN driver, a transport that performs communication between servers using a logical address uniquely assigned to each server, and LAN of the main server
Without using an interface, the LAN of the standby server
A communication management unit of the main server that performs communication by the communication management unit of the standby server via a communication link using an interface, and a standby that performs communication of the main server using the LAN interface of the standby server. A communication management unit of a system server, wherein when a failure occurs in the main server and communication through the LAN is impossible, but processing can be continued, the main server and another client Is performed using the LAN interface of the standby server to continue the processing of the primary server.

By having such a communication control function, there is no need to notify other computers on the LAN in order to change the combination of the transport logical address and the LAN physical address. When a plurality of transports are used, processing is required for each transport. However, in the present invention, transmission and reception of packets are replaced at the level of the physical address of the LAN.
There is no need for that.

(3) In order to achieve the above object, the present invention provides the above-mentioned client-server system, wherein the client-server system has a plurality of ports connected to a LAN interface of a computer, By storing the address and sending the packet addressed to the stored physical address only to the port to which the physical address is connected, not to all the ports of the Ethernet switch,
A LAN switch for reducing the number of packets in the LAN and providing a larger communication band, and a LAN interface of a main server and a standby server are connected to the LAN through the LAN switch.

By having such a communication control function, the number of packets arriving at the standby LAN interface is reduced by using the LAN switch, and the load on the standby server and its LAN interface can be reduced.

(4) In order to achieve the above object, the present invention provides the above-mentioned client-server system, which has a plurality of ports to which a LAN interface of a computer is connected, and performs conversion for performing packet address conversion. An address conversion table for storing a physical address to be replaced and an address to be replaced with the address, and a filter for converting the address of a packet transmitted from each port by referring to the address conversion table and transmitting the address to all ports The address translation is performed by translating the addresses of the packets for all the packets received from the port, transmitting the translated packets to all the ports, and receiving the packet addressed to itself from the computer via the LAN. The feature is that the table part can be changed dynamically, By having a communication control function, such as, it can convert physical address of the packet, and can do so dynamically.

(5) Further, in order to achieve the above-mentioned object, the present invention provides the above-mentioned client-server system, wherein the LAN interface of the main server and the standby server is connected to the LAN through the above-mentioned packet filter device. In the event of a failure of the primary server, the standby server transmits and receives the logical addresses of the transports of both the primary server and the standby server, and converts the physical address by a packet filter device. And

By having such a communication control function, the logical address managed by the transport can be taken over, but it is not necessary for another client on the LAN to change the combination of the logical address and the physical address.

[0020]

Embodiments of the present invention will be described below with reference to the drawings. In this embodiment, the main server and the standby server are named for simplicity of explanation. However, there is no essential difference between the main server and the standby server. It is possible to do. (First Embodiment) FIG. 1 is a block diagram showing a system configuration in an embodiment of the present invention. Here, each component of the primary server 1 will be mainly described, but the standby server 10 may have exactly the same configuration.

In each of the servers 1 and 10, the transports 5 and 14 serve to transfer packets received via the LAN interfaces 2 and 11 and the LAN drivers 3 and 12 to the server processes 7 and 16. . Here, the transport is assumed to be TCP / IP for easy understanding.

The LAN interfaces 2 and 11 are LAN
This is a device that transmits and receives packets to and from the PC 21. When a packet addressed to a physical address designated in advance is transmitted on the LAN 21, the packet is received and notified to the LAN drivers 3 and 12. Also, the packet transmitted from the LAN drivers 3 and 12 is transmitted to the LAN 21. Here, it is assumed that the LAN is Ethernet for easy understanding.

The LAN drivers 3 and 12 control the LAN interfaces 2 and 11. The packets received by the LAN interfaces 2 and 11 are transferred to the transports 5 and 14
Processed into data that can be used by
4. Transfer to communication management units 4 and 13. Further, a packet to be transmitted on the LAN 21 is created from the data passed from the transports 5 and 14, and
Is transmitted on the LAN 21 via the. Further, when the LAN interfaces 2 and 11 are used, the failure is detected and notified to the communication management units 4 and 13.

The communication link 20 is connected to each of the servers 1 and 10
This is a dedicated link for communication between. The server processes 7 and 16 provide services that can be used from other computers on the network. For example, a database service is performed. A plurality of server processes 7 and 16 may exist, and the content of the service may be different between the primary server 1 and the standby server 10.

The client 22 is a computer that uses the services of the main server 1 and the standby server 10 via the LAN. There can be multiple clients. The communication management units 4 and 13 hold the state of the failure of the main server 1 and the standby server 10, and control processing when the server is normal and when a failure occurs. There are four states in which both servers are normal, a failure has occurred in the own server, a failure has occurred in the other server, and a failure has occurred in both servers. Although there are various types of failures and various detections, in the embodiment of the present invention, only the case where only communication processing through the LAN 21 cannot be performed is relevant. Therefore, only a case where communication processing via the LAN 21 cannot be performed and all other processing can be performed is treated as a failure.

For example, this failure occurs when the LAN interface 2 becomes unusable. A failure of the LAN interface 2 can be detected when the LAN driver 3 transmits and receives a packet.

Further, the cluster control unit 6 periodically updates the LA
A method of inspecting the LAN interface 2 through the N driver 3 can be adopted. Further, a method of transmitting data from the standby server 10 to the main server 1 via the LAN 21 and inspecting the contents thereof to check whether the operation is correct or not may be considered.

There are various methods for diagnosing recovery from a failure. For example, a packet is transmitted from the LAN interface 11 of the standby server 10 where no failure has occurred to the LAN interface 2, and it is periodically checked whether the packet can be received. Alternatively, it is conceivable to periodically perform a process of checking whether or not the main server 1 has recovered from the failure.

In the present invention, the occurrence of a failure and the recovery are detected by the hardware of the main server 1 or software such as the LAN driver 3 and the communication management unit 4 is notified.
Alternatively, the communication management unit 4 performs the processing by itself.

FIG. 4 shows a state change of the communication management unit 4. When the communication management unit 4 detects a failure of the primary server 1 (own server), the communication management unit 4 enters a failure state in the own server and notifies the communication management unit 13 of the standby server 20 via the communication link 20.

Upon receiving the notification, the communication management unit 13 of the standby server 20 enters a failure state in another server (RB).
When recovery from the failure occurs, the status of both servers is set to normal, and the communication management unit 13 is notified in the same manner as the failure notification.

Upon receiving the notification, the communication management unit 13 changes to a state where both servers are normal (RA). If both servers are out of order, it is only possible to have a plurality of LAN interfaces as described later. Here, for the sake of explanation, there is one LAN interface, and in the case of a plurality, only the difference will be described later. Therefore, if both servers fail, communication cannot be taken over.

The communication management unit 4 is a part for switching communication at the time of failure, which is a feature of the present invention. Communication management unit 4
Is located between the LAN driver that controls the actual communication to the LAN and the transport, and controls the exchange of data between them. In the event of a failure, the communication link 20
The communication with the communication management unit 13 is performed through the.

The communication management unit 4 can detect a failure of the LAN interface 2 through the LAN driver 3. Further, the address of the received packet from the LAN passed from the LAN driver 3 can be checked. Further, since the LAN driver 3 has a function of only transmitting the passed packet to the LAN, the address of the transmitted packet can be checked. Can also be changed.

FIG. 5 is a flowchart showing the operation processing procedure of the communication management section 4. In steps 60 and 62, it is determined whether the notification is a failure notification or transmission or reception processing. Step 66
Is a reception process. Also, it processes both the notification from the communication management unit of the other server and the own server, and the transmission and reception of data. For example, when data is sent to another server in step 70, the communication management unit of the other server enters the processing of step 62 as transmission processing and executes the flow of steps 64 and 65 as a failure of another server.

Next, a communication method will be described for normal time and for failure. The normal processing will be described with reference to the conceptual diagram showing the normal communication processing in FIG. Communication management units 4 and 13
Both servers are in a normal state, and each server communicates using a built-in LAN interface.

The data transmitted by the server process is processed by the transport 5, the communication management unit 4, and the LAN driver 3, and transmitted through the LAN interface 2 to the LAN 2.
1 is transmitted. The packet arriving at the LAN interface 2 from the LAN 21 reaches the server process 7 by following the reverse route.

The communication management unit 4 is in a state where both servers are normal, and transmits data to be transmitted and received to the transport 5 and the LA.
Only the relay between the N drivers 3 is performed. Next, the processing at the time of failure will be described with reference to a conceptual diagram showing communication processing at the time of failure occurrence in FIG. The communication management unit 4 detects the failure and sets the state to the own server failure.

Next, the occurrence of a failure is notified to the communication management unit 13 through the communication link 20. A physical address that the other party wants to take over is transmitted together with the notification. Upon receiving the failure notification, the communication management unit 13 enters a state of another server failure.

The communication management unit 4 in which the own server has failed.
Sends the data to be transmitted to the LAN 21 transmitted from the server process 7 or the like to the communication management unit 13 through the communication link 20. Conversely, it passes the received data sent from the communication management unit 13 to the server process 7.

The communication management unit 13 in the state of another server failure transmits and receives packets arriving from the LAN 21 to the physical address of the LAN interface 11 and packets output by the server process 16 in the same manner as normal. When the failure notification is received from the main server 1, the setting is changed using the LAN driver 12 so that the LAN interface 11 also receives the packet addressed to the physical address of the LAN interface 2.

The packet transmitted from the communication management unit 4 through the communication link 20 is transmitted from the LAN interface 11 as a packet transmitted from the physical address of the LAN interface 2. Specifically, a packet in which the physical address of the LAN interface 2 is included in the address of the sender of the packet is transmitted to the LAN 21.

LA received by LAN interface 11
The communication management unit 13 can determine whether the packet addressed to the N interface 2 is addressed to the main server 1 or the standby server 10 by checking the destination of the packet. Those destined for the standby server 10 are passed to the transport 14 as they are, similarly to the normal processing. Primary server 1
Those destined for the communication management unit 4 via the communication link 20
Send to

The case where the failure of the main server 1 is eliminated and the main server 1 can resume communication will be described.
It is assumed that the communication management unit 4 detects that the failure has disappeared. The communication management unit 13 is notified by using the communication link 20, and the status of both communication management units is set to the normal state of both servers.

The subsequent data transmission / reception is performed by each server using its own LAN interface as shown in FIG. It is possible to cope with a case where there are a plurality of LAN interfaces. However, main server 1
The standby server 10 must also be connected to the LAN to which is connected.

When the communication management unit 4 sends a failure notification to the communication management unit 13 of the standby server 10 together with information indicating the LAN interface connected to which LAN has failed, In the manner described, the standby server 10 can take over the transmission and reception of the main server 1. In this case, the operation may be determined while retaining information on which LAN cannot communicate with.

Depending on the type of the LAN interface,
In some cases, only one physical address received from the LAN 21 can be set. The above description is based on the premise that two physical addresses can be received for the main server 1 and the standby server 10. In this case, the LAN driver 12 of the standby server 10
The interface is changed to a mode for receiving all packets transmitted to the LAN 21.

The LAN driver 12 relays all the received packets to the communication management unit 13. Communication management unit 13
Can solve this problem by performing a process of selecting only a packet addressed to the standby server 10 and a packet addressed to the main server 1 from the received packets.

As described above, according to the present embodiment, when a failure occurs in the primary server 1 and communication processing cannot be performed, communication processing can be continued through the LAN interface 11 of the standby server 10. .

Also, since the physical address of the LAN 21 is taken over instead of the logical address used by the transport, it is not necessary to notify other computers on the LAN 21 and change the combination of the logical address and the physical address. Good.

Further, depending on the client 22, there may be a case where a combination of a logical address and a physical address is statically held therein and cannot be changed by a notification from the standby server 10. In this embodiment, the standby server 10 performs reception in place of the main server 1 without changing this combination of clients. It is. (Second Embodiment) In the first embodiment described above,
Depending on the type of LAN interface, there is a type that can receive only one physical address. When the standby server having such a LAN interface also tries to receive a packet addressed to the physical address of the primary server as in the first embodiment, it receives all the packets as described above, and From the middle, L of the standby server
It is necessary for the communication management unit to perform a process of selecting a packet addressed to the physical address of the AN interface and a packet addressed to the physical address of the LAN interface of the primary server.

In this case, the LAN interface is LAN
To receive all the above packets, there is a problem that the number of processes becomes very large, and the communication management unit of the standby server also has a very large number of processes.

Therefore, as shown in FIG. 6, a system configuration using a generally used LAN switch 30 will be described as a second embodiment. In FIG. 6, the same components as those in the first embodiment are denoted by the same reference numerals as in FIG. 1, and the description thereof is omitted.

Here, the LAN switch 30 is an Ethernet switch used for Ethernet. The Ethernet switch has a plurality of ports connected to the LAN interface of the computer. At the end of the port, not only one computer but also a plurality of computers connected by a hub may be used.

The Ethernet switch scans a packet output from a port and stores a physical address of a LAN interface of a computer connected to each port for each port.

When the Ethernet switch receives a packet addressed to a physical address stored as being connected to each port,
Only send packets to that port, not other packets.

In a normal hub or the like, a packet is always transmitted to all ports, but by transmitting a packet only to the port connected as described above, unnecessary traffic can be suppressed.

At the normal time and at the time of failure, the same operation as in the first embodiment is performed. However, the communication management unit 13 is the main server 1
When starting the operation to take over the communication of LAN2,
1 transmits a packet having the physical address of the LAN interface 2 of the main server 1 as a source address to the broadcast or the LAN interface 11.

As a result, the LAN switch 30
LA to the packet addressed to the physical address of N interface 2
It learns to transmit to the port to which the N interface 11 is connected.

As described above, the present embodiment has the following effects in addition to the effects of the first embodiment. That is, the number of packets arriving at the LAN interface of the standby server is reduced due to the filtering of the packet performed by the Ethernet switch, and the processing of the standby server at the time of failure is reduced as compared with the case of the first embodiment. (Third Embodiment) As described in the related art, when a logical address is substituted, the logical address can be substituted without affecting the client 22 on the LAN.

This embodiment will be described with reference to FIGS. This embodiment has a system configuration in which a packet filter 40 is added to the configuration of the first embodiment. In the figure, the same components as those in the first embodiment are denoted by the same reference numerals as in FIG. 1, and the description thereof will be omitted.

First, referring to FIG.
0 will be described. As shown in FIG. 8, the packet filter 40 has a plurality of ports 41 to which the LAN interface of the computer is connected, and stores an address conversion table 42 for storing the addresses of the packets to be converted. And a filter 43 for rewriting the data based on the address conversion table 42.

The packet filter 40 is connected to the normal LAN 2
As with one hub, a packet arriving from one port is transmitted to all other ports. At that time, the address conversion table 42
When a packet having the destination registered in the original address 51 of the destination arrives, the destination is set to the new address 5.
2 and transmit to all ports. Also, the same conversion is performed on the source address of the packet.

In order to instruct the packet filter 40 to replace the address as described above, the packet filter 4
0 has a physical address identifying itself. LAN21
In order to control the packet filter 40, the computer connected to the packet filter stores the original address and the new address in a packet addressed to the physical address of the packet filter 40 and transmits the packet.

The packet filter 40 receives the packet and registers it in the address conversion table 42. When a packet containing data having the same address as the original address (address value is A) and the new address is received, an entry whose original address is A in the address conversion table 42 is searched. , Delete it.

Incidentally, the packet filter 40 may be configured to have the function of the LAN switch described in the second embodiment. The communication management units 4 and 13 normally
The operation is the same as in the first embodiment.

Next, the case of a failure will be described. As in the first embodiment, it is assumed that the main server 1 has failed. The failure notification, the state change of the communication management units 4 and 13, and the operation of the communication management unit 4 of the main server 1 are the same as those in the first embodiment.

What is different is the operation and position of the communication performed by the communication management unit 13 of the standby server 10. This will be described with reference to FIG. The communication management units 4 and 13
Located between transport and server process.

When the communication management unit 13 receives the failure notification from the communication management unit 4, the transport 14 can also receive a packet addressed to the logical address (the IP address in TCP / IP) of the transport 5 of the main server 1. To instruct.

The transport 14 such as TCP / IP generally used can handle a plurality of logical addresses, so that no special mechanism is required.

In a normal transport, another client on the LAN caches a set of a logical address and a physical address of a machine on the LAN in order to increase efficiency.

When the standby server 10 starts using a new logical address, especially in the present embodiment, the cache is discarded in order to take over the logical address already paired with the physical address of the primary server 1. Required. In order to discard these caches, operations such as broadcasting and transmitting a packet to a LAN are usually performed.

It is not necessary to perform the operation for updating the cache of the set of the logical address and the physical address which the client on the LAN may hold. The reason will be described below.

Next, the communication management section 13 sends the physical address of the LAN interface 2 of the primary server 1 to the packet
A packet including a set of data having the new physical address of the AN interface 11 is transmitted.

The packet filter 40 receives this packet and records the set of physical addresses in the address conversion table 42. By doing so, it is guaranteed that the packet destined for the LAN interface 2 reaches the LAN interface 11 by the packet filter 40.
Therefore, the client on the LAN is the LA of the main server 1
Although the packet continues to be transmitted to the N interface 2, it is the standby server 10 that actually receives the packet.

The packet received by the LAN interface 11 reaches the communication manager 13 through the LAN driver 12 and the transport 14. The communication management unit 13 can determine whether the packet is addressed to the main server or the standby server by looking at the logical address of the destination of the packet, and distributes the packet to each.

Next, a case where the failure of the main server 1 is corrected will be described. At this time, the communication management unit 4 notifies the communication management unit 13 when detecting that the failure has been corrected, as in the first embodiment.

The communication management unit 13 instructs the transport 14 to stop handling the logical address of the primary server 1 which has been replaced by the transport 14 so far.
Notify 4.

Further, the packet filter 40 transmits a packet which is the physical address of the LAN interface 2 of the primary server 1 to both the original address and the new address to the packet filter 40 to stop the translation of the packet address. To instruct.

Thus, the transfer of the packet by the packet filter 40 is stopped, the packet can be received by the primary server 1, and the standby server 10 can return to a state where only the packet addressed to itself can be received. .

According to the above-described embodiment, the standby server can receive the packet of the primary server without affecting the cache of the logical address and the physical address held by the client.

Further, as described in the first and second embodiments, the LA which can designate only one physical address to be received can be specified.
When using the N interface, there is no need to use the mode for receiving all packets. (Fourth Embodiment) In all the above-described embodiments, the primary server 1 and the standby server 10 use the dedicated communication link 20 at the time of failure to transmit data for substituting for communication by the standby server 10. Was exchanging.

In this embodiment, the main server 1 and the standby server 10 are connected to a plurality of LANs, and even if a failure occurs in a plurality of LAN interfaces and communication becomes impossible, at least one If there is a LAN that can communicate, the above-described failure notification and data exchange can be performed using a LAN instead of a dedicated communication link. According to this embodiment, no dedicated communication link is required between the primary server and the standby server.

Note that. Since the technique of the present invention can be implemented as software, it can be stored in a computer-readable recording medium such as a floppy disk, an optical disk, or a semiconductor memory and distributed as a program that can be executed by a computer. It is. Then, the computer that has read the contents of the recording medium realizes the execution of the above-described processing by controlling the execution of the read program.

[0085]

As described above, according to the present invention, the logical address (I / O) of the transport (such as TCP / IP) is
There is no need to notify other computers on the LAN in order to change the combination of the P address) and the physical address of the LAN. Further, when a plurality of transports are used, processing is required for each transport. However, in the present invention, transmission and reception of packets are replaced at the level of the physical address of the LAN, so that this is not necessary.

According to the present invention, by using the LAN switch, the number of packets arriving at the standby LAN interface is reduced, and the load on the standby server and its LAN interface can be further reduced.

Further, according to the present invention, the physical address of a packet can be translated and can be dynamically performed. Further, according to the present invention, there is an effect that the logical address managed by the transport is taken over, but it is not necessary for another client on the LAN to change the combination of the logical address and the physical address.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of a system according to a first embodiment of the present invention.

FIG. 2 is a conceptual diagram showing a normal communication process in the embodiment.

FIG. 3 is a conceptual diagram showing communication processing when a failure occurs in the embodiment.

FIG. 4 is a state transition diagram in the embodiment.

FIG. 5 is a flowchart showing a processing procedure of a communication management unit in the embodiment.

FIG. 6 is a block diagram showing a configuration of a system using a LAN switch according to a second embodiment of the present invention.

FIG. 7 is a block diagram showing a configuration example using a packet filter according to a third embodiment of the present invention.

FIG. 8 is a diagram showing a configuration of a packet filter in the embodiment.

FIG. 9 is a diagram showing a configuration of an address conversion table in the embodiment.

FIG. 10 is a conceptual diagram showing communication processing at the time of failure in the embodiment.

FIG. 11 is a conceptual diagram showing communication processing by a conventional system.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Main server, 2 ... LAN interface, 3 ... LAN driver, 4 ... Communication management part, 5 ... Transport, 6 ... Cluster control part, 7 ... Server process, 10 ... Stand-by server, 11 ... LAN interface, 12 ... LAN driver, 13 ... communication management unit, 14 ... transport, 16 ... server process, 20 ... communication link, 21 ... LAN, 22 ... client, 30 ... LAN switch, 40 ... packet filter, 41 ... port, 42 ... address Conversion table, 43 ... Filter.

Claims (12)

[Claims] 1. In a client server system,
When a failure occurs in the primary server and the communication device of the standby server performs the communication process of the primary server instead, the LAN
The standby server replaces the communication process of the primary server without notifying the client when the communication of the primary server is transmitted / received using the physical address used in the communication, and the communication failure of the primary server occurs. A method for controlling a client-server system, characterized in that: 2. A client server system having a main server and a standby server, comprising: a dedicated communication link connecting the main server and the standby server; and a LAN interface of each server. LAN to control
A driver, a transport for performing communication between the servers using a logical address uniquely assigned to each of the servers, and a LAN of the main server when a failure occurs in the main server
Without using an interface, the LAN of the standby server
A communication management unit of the main server that communicates with the communication management unit of the standby server via a communication link so as to use an interface; and a standby that communicates with the main server using a LAN interface of the standby server. A communication management unit of a system server, wherein when a failure occurs in the main server and communication through the LAN is not possible, but processing can be continued,
A client server system wherein communication between the main server and another client is performed by using a LAN interface of the standby server to continue processing of the main server. 3. A computer having a plurality of ports connected to a LAN interface of the computer, storing a physical address of the LAN interface at the port destination, and transmitting a packet addressed to the stored physical address to all ports of the Ethernet switch. The LAN switch of the main server and the standby server, which sends a packet only to the port to which the physical address is connected to reduce the number of packets in the LAN to provide a larger communication band, 3. The client server system according to claim 2, wherein the client server system is connected to the LAN through the LAN switch. 4. An address translation table unit having a plurality of ports to which a LAN interface of a computer is connected, and holding a physical address to be translated and an address to be replaced with the address in order to perform packet address translation;
A filter unit that translates the address of a packet sent from each port with reference to the address conversion table unit and transmits the translated address to all ports, and performs packet address conversion for all packets received from the port. A packet filter device which is capable of dynamically changing the address conversion table section by transmitting the converted packet to all ports and receiving a packet addressed to itself through the LAN from the computer. . 5. The system according to claim 4, wherein the LAN interface between the primary server and the standby server is connected to the LAN through the packet filter device. When the primary server fails, the standby server is connected to the primary server and the standby server. 3. The client server system according to claim 2, wherein logical addresses of both transports of the system server are transmitted and received, and physical addresses are converted by a packet filter device. 6. A main server that processes a request sent from an arbitrary client via a LAN and returns a result of the processing, and a main server that stops processing or a communication device of the main server fails. In a client server system comprising a standby server for transmitting and receiving data to and from a client instead of the primary server and connected to each other through the LAN, the primary server and the standby server are connected by a dedicated communication link. Each of the servers has a LAN interface, and each server performs inter-server communication using a logical address uniquely assigned to the server, and a failure occurs in the main server and communication via the LAN is impossible. If it is possible to continue the processing, the communication between the primary server and another client is performed by the standby server. AN
A communication method switching method, wherein the processing of the primary server is continued by using an interface. 7. A computer having a plurality of ports connected to a LAN interface of a computer, storing a physical address of the LAN interface of the port destination, and transmitting a packet addressed to the stored physical address to all of the Ethernet switches. By sending only to the port to which the physical address is connected, not to the port, the packets in the LAN are reduced to provide a larger communication band, and the LAN interfaces of the primary server and the standby server are connected to the LAN. 7. The communication method switching method according to claim 6, wherein the communication method is switched. 8. The system according to claim 4, wherein the LAN interface between the main server and the standby server comprises a system for connecting to the LAN through the packet filter device, and when the main server fails, the standby server becomes the main server. 7. The communication method switching method according to claim 6, further comprising transmitting and receiving a logical address of both transports of the standby server and converting a physical address by a packet filter device. 9. A program for controlling the operation of a client-server system, wherein a failure occurs in a primary server and a communication device of a standby server performs communication processing of the primary server instead. LAN
By transmitting and receiving packets addressed to the primary server using the physical address used in the server, when a communication failure occurs in the primary server, the communication process of the primary server is performed without being notified to the client. A computer-readable recording medium on which a program for operating the client server system is recorded. 10. A main server that processes a request sent from an arbitrary client via a LAN and returns a result of the processing. If the main server stops or a communication device of the main server breaks down, A program for controlling the operation of a client server system comprising a standby server for transmitting and receiving data to and from a client instead of the main server, wherein the main server and the standby system The servers are connected by a dedicated communication link, each of the servers has a LAN interface, and each server performs a server-to-server communication using a logical address uniquely assigned to each of the servers. If communication through the LAN is not possible but processing can be continued, the main server and another client Communication with, LAN of the standby server
A computer-readable recording medium that records a program for controlling switching of a communication system of the client server system so as to continue processing of the primary server by using an interface. 11. The program according to claim 1, wherein the client server system is configured to execute an L operation between the primary server and the standby server.
When the AN interface has a plurality of ports to be connected, the physical address of the LAN interface at the port destination is stored, and the packet addressed to the stored physical address is not transmitted to all the ports of the Ethernet switch.
By transmitting only to the port to which the physical address is connected, the number of packets in the LAN is reduced to provide a larger communication band, and the LAN of the primary server and the standby server is provided.
11. The computer-readable recording medium according to claim 10, wherein the communication method switching of the client server system is controlled so that the interface connects to the LAN. 12. The program according to claim 1, wherein the client server system is configured to execute an L operation between the main server and the standby server.
When the AN interface connects to the LAN through the packet filter device according to claim 4, when the primary server fails, the standby server transmits and receives the logical addresses of the transports of both the primary server and the standby server. 11. The computer-readable recording medium according to claim 10, wherein the communication method switching of the client server system is controlled so as to perform the conversion of the physical address by the packet filter device.