System and method for clustered failover without network support

• US 7,039,828 B1
• Filed: 02/28/2002
• Issued: 05/02/2006
• Est. Priority Date: 02/28/2002
• Status: Active Grant

• Current Assignee: Network Appliance Incorporated (NetApp, Inc.)
• Original Assignee: Network Appliance Incorporated (NetApp, Inc.)
• Inventors: Scott, John A.
• Primary Examiner(s): Baderman, Scott
• Assistant Examiner(s): Contino, Paul F.
• Application Number:
  US10/086,657
• Time in Patent Office: 1,524 Days
• Field of Search: 714/4, 714/43, 709/227, 709/228
• US Class Current: 714/4.11
• CPC Class Codes: G06F 11/1443 Transmit or communication errors
• CPC Class Codes: G06F 11/2028 eliminating a faulty processor or activating a spare
• CPC Class Codes: G06F 11/2033 switching over of hardware resources
• CPC Class Codes: G06F 11/2035 without idle spare hardware
• CPC Class Codes: G06F 11/2046 where the redundant components share persistent storage G06F11/2043 takes precedence
• CPC Class Codes: H04L 2101/30 Types of network names
• CPC Class Codes: H04L 2101/365 Application layer names, e.g. buddy names, unstructured names chosen by a user or home appliance name
• CPC Class Codes: H04L 61/30 Managing network names, e.g. use of aliases or nicknames name-to-address mapping H04L61/45
• CPC Class Codes: H04L 61/35 involving non-standard use of addresses for implementing network functionalities, e.g. coding subscription information within the address or functional addressing, i.e. assigning an address to a function
• CPC Class Codes: H04L 61/4511 using domain name system [DNS]
• CPC Class Codes: H04L 67/1097 for distributed storage of data in networks, e.g. transport arrangements for network file system [NFS], storage area networks [SAN] or network attached storage [NAS]
• CPC Class Codes: H04L 69/40 for recovering from a failure of a protocol instance or entity, e.g. service redundancy protocols, protocol state redundancy or protocol service redirection management of faults, events, alarms or notifications in data switching networks H04L41/06

Abstract

A system and method for clustered failover over transport media that does not support moving of transport addressed between network interface controllers is provided. This reviving file server of a cluster, upon detection of the failure of its partner, assumes ownership of the disks owned by the failed file server. The surviving file server activates a secondary discriminator or port for access by clients who normally utilized the failed file server. Clients generate the name of the surviving or failover file server by appending at set item to the name of the failed file server.

Claims

1. A method for a first file server to provide file service operations normally performed by a second file server after the second file server suffers an error condition, the first and second file servers operatively interconnected with a set of clients using a network protocol, the network protocol being free of support for moving a transport address from the second file server to the first file server, the method comprising the steps of:

detecting, by the first file server, that the second file server has suffered an error condition;

asserting ownership, by the first file server, of a set of storage devices normally owned by the second file server;

activating, on the first file server, a secondary data access port for receiving connections over a network; and

processing, by the first file server, file service operations directed to the secondary data access port from a set of failover clients, the failover clients accessing the first file server by computing a network address associated with the first file server from a first symbolic name, the first symbolic name generated by the failover client from a second symbolic name associated with the second file server, whereby failover operation is achieved by the client.

2. The method of claim 1 wherein the step of detecting the error condition further comprises the steps of sending, by the second file server, an error message to the first file server.

3. The method of claim 1 wherein the step of detecting an error condition further comprises the step of:

detecting, by the first file server, a lack of a status signal generated by the second file server.

4. The method of claim 1 wherein the secondary data access port is a virtual interface discriminator.

5. A method for a client to continue to access file service operations after a first file server has suffered an error condition, the method comprising the steps of:

computing a failover name by appending a set text string to a name of the first file server;

resolving the failover name to a network address;

connecting to a failover file server using the network address and a predetermined alternate data access port.

6. The method of claim 5 wherein the predetermined alternate data access port further comprises a virtual interface discriminator.

7. A computer-readable medium, including program instructions executing on a client, for the client to continue to access file service operations after a first file server has suffered an error condition, the instructions including steps for:

computing a failover name by appending a set text string to a name of the first file server;

resolving the failover name to a network address; and

connecting to a failover file server using the network address and a predetermined alternate data access port.

8. A method for operating a computer failover system, comprising:

executing a client computer program on a client computer, the client computer program communicating with a first file server, the first file server associated with a file server name;

computing from the file server name, by a file system process on the client computer, a failover name associated with a failover file server;

resolving the failover name to a network address;

detecting an error condition; and

connecting, in response to detecting the error condition, to a failover file server port having the network address.

9. The method as in claim 8, further comprising:

computing the failover name by modifying the file server name by an alphanumeric text.

10. The method as in claim 8, further comprising:

computing the failover name by appending the text “

backup”

to the file server name used to communicate with the first file server.

11. The method as in claim 8, further comprising:

transmitting the failover name to a distributed naming service to perform the step of resolving the failover name to a network address.

12. The method as in claim 8, further comprising:

using a database program as the client computer program.

13. The method as in claim 8, wherein the step of detecting the error condition further comprises:

detecting a lack of a heartbeat signal from a failed file server.

14. The method as in claim 8, wherein the step of detecting the error condition further comprises:

transmitting by a failing file server an “

I am failing”

message.

15. A computer failover system, comprising:

means for executing a client computer program on a client computer, the client computer program communicating with a first file server, the first file server associated with a file server name;

means for computing from the file server name, by a file system process on the client computer, a failover name associated with a failover file server;

means for resolving the failover name to a network address;

means for detecting an error condition; and

means for connecting, in response to detecting the error condition, to a failover file server port having the network address.

16. The system as in claim 15, further comprising:

means for computing the failover name by modifying the file server name by an alphanumeric text.

17. The system as in claim 15, further comprising:

means for computing the failover name by appending the text “

backup”

to the file server name used to communicate with the first file server.

18. The system as in claim 15, further comprising:

means for transmitting the failover name to a distributed naming service to perform the step of resolving the failover name to a network address.

19. The system as in claim 15, further comprising:

means for using a database program as the client computer program.

20. The system as in claim 15, further comprising:

means for detecting a lack of a heartbeat signal from a failed file server.

21. The system as in claim 15, further comprising:

means for sending, by a failing file server, an error message to the first file server.

22. The system as in claim 15, further comprising:

means for transmitting by the failing file server an “

I am failing”

message.

23. A computer failover system, comprising:

a client computer having a client computer program executing thereon, the client computer program communicating with a first file server, the first file server associated with a file server name;

a file system process on the client computer, the file system process computing from the file server name a failover name associated with a failover file server;

a port to transmit the failover name to a distributed name server to resolve the failover name to a network address;

a port to receive a message reporting an error condition in the first file server; and

a file system process to use the failover name and network address to connect, in response to the error condition, to a failover file server port having the network address.

24. The system as in claim 23, further comprising:

a file system process to compute the failover name by modifying the file server name by an alphanumeric text.

25. The system as in claim 23, further comprising:

a file system process to compute the failover name by appending the text “

backup”

to the file server name used to communicate with the first file server.

26. The system as in claim 23, further comprising:

a file system process to transmit the failover name to a distributed naming service to perform the step of resolving the failover name to a network address.

27. The system as in claim 23, further comprising:

the client computer program is a database program.

28. The system as in claim 23, further comprising:

means for detecting a lack of a heartbeat signal from a failed file server.

29. The system as in claim 23, further comprising:

means for sending, by a failing file server, an error message to the first file server.

30. The system as in claim 23, further comprising:

means for transmitting by the failing file server an “

I am failing”

message.

31. A computer readable media, comprising:

said computer readable media containing instructions for execution on a processor for the practice of a method for operating a computer failover system, the method having the steps of,

executing a client computer program on a client computer, the client computer program communicating with a first file server, the first file server associated with a file server name;

computing from the file server name, by a file system process on the client computer, a failover name associated with a failover file server;

resolving the failover name to a network address;

detecting an error condition; and

connecting, in response to detecting the error condition, to a failover file server port having the network address.

32. A client interconnected to a first file server and to a second file server, the client comprising:

means for detecting the first file server has suffered an error condition;

means for computing a failover name by appending a set text string to a name of the first file server;

means for resolving the failover name to a network address;

means connecting to a failover file server using the network address and a predetermined alternate data access port.

33. The client of claim 32 wherein the predetermined alternate data access port further comprises a virtual interface discriminator.

34. A method for a first file server to provide file service operations normally performed by a second file server after the second file server suffers an error condition, the method comprising:

detecting, by the first file server, that the second file server has suffered an error condition; and

processing, by the first file server, file service operations from a set of failover clients, the failover clients accessing the first file server by computing a network address associated with the first file server from a first symbolic name, the first symbolic name generated by appending a set text string to a second symbolic name of the second file server.

35. The method of claim 34 further comprising:

activating, on the first file server, a secondary data access port for receiving connections over a network; and

servicing file service operations from the set of failover clients using the secondary data access port.

36. The method of claim 34 further comprising:

asserting ownership, by the first file server, of a set of storage devices normally owned by the second file server.

37. The method of claim 34 further comprising:

transmitting the first symbolic name to a distributed naming service to compute the network address.

38. The method as in claim 34, wherein the step of detecting further comprises:

detecting a lack of a heartbeat signal from the second file server.

39. The method as in claim 34, wherein the step of detecting further comprises:

transmitting by the second file server a message indicating that failover should begin.

40. A computer failover system allowing a first file server to provide file service operations normally performed by a second file server after the second file server suffers an error condition, the system comprising:

means for detecting, by the first file server, that the second file server has suffered an error condition; and

means for processing, by the first file server, file service operations from a set of failover clients, the failover clients accessing the first file server by computing a network address associated with the first file server from a first symbolic name, the first symbolic name generated by appending a set text string to a second symbolic name of the second file server.

41. A computer-readable medium comprising program instructions executing for execution on a processor for the practice of a method for operating a computer failover system, the method having the steps of:

detecting, by a first file server, that a second file server has suffered an error condition; and

processing, by the first file server, file service operations from a set of failover clients, the failover clients accessing the first file server by computing a network address associated with the first file server from a first symbolic name, the first symbolic name generated by appending a set text string to a second symbolic name of the second file server.