Network block services for client access of network-attached data storage in an IP network

• US 20040059822A1
• Filed: 09/25/2002
• Published: 03/25/2004
• Est. Priority Date: 09/25/2002
• Status: Active Grant

• Current Assignee: Emc IP Holding Company LLC (Dell Technologies Inc.)
• Original Assignee: EMC Corporation (Dell Technologies Inc.)
• Inventors: Jiang, Xiaoye, Venkatesh, Dinesh, Ku, Mark K., Chen, Xiangping
• Granted Patent: US 7,475,124 B2
• Time in Patent Office: Days
• US Class Current: 709/230
• 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 69/16 Implementation or adaptation of Internet protocol [IP], of transmission control protocol [TCP] or of user datagram protocol [UDP]
• CPC Class Codes: H04L 69/161 Implementation details of TCP/IP or UDP/IP stack architecture; Specification of modified or new header fields
• CPC Class Codes: H04L 69/329 in the application layer [OSI layer 7]

Abstract

The SCSI and iSCSI layers over the TCP/IP layers of the protocol stack in an IP network client and in an IP network-attached storage server are replaced with a thin network block services layer. The network block services layer 71 implements a network block services protocol having a very reduced set of commands transmitted between the client and the storage server. The network block services protocol is used in a configuration process in which logical volumes of the network-attached storage are exported to the client and become local pseudo-disk instances. The client'"'"'s operating system and application programs access the local pseudo-disk instances with what appears to be a standard device driver for a local disk device. The device driver maintains a TCP connection to each open device, and responds to connection failure by re-connecting with an alternative server IP port.

Claims

1. A data processing system comprising a client, a storage server, and an Internet Protocol (IP) network linking the client to the storage server for client access to storage in the storage server, the storage including storage units allocated to the client, the storage server containing an identification of the storage units allocated to the client, the client and the storage server each being programmed with a protocol stack, each protocol stack including a network block services layer over an IP layer, the network block services layer encoding and decoding IP packets transmitted over the IP network between the client and the server in accordance with a network block services protocol, the IP packets transmitted over the IP network between the client and the server in accordance with the network block services protocol including IP packets for requesting the identification of the storage units allocated to the client, IP packets for reading data from the storage units allocated to the client, and IP packets for writing data to the storage units allocated to the client, the client being programmed for configuring the identified storage units allocated to the client into pseudo-disk instances after obtaining from the storage server the identification of the storage units allocated to the client by invoking the network block services layer to request from the storage server the identification of the storage units allocated to the client, and the client being further programmed with a block interface for enabling an operating system or application program of the client to access the pseudo-disk instances by invoking the network block services layer to read data from the storage units allocated to the client and for writing data to the storage units allocated to the client.

2. The data processing system as claimed in claim 1, wherein the storage units are logical volumes of storage.

3. The data processing system as claimed in claim 1, wherein the IP network links a plurality of clients to the storage server for access to the storage of the storage server, and wherein the storage of the storage server contains, for each of the clients, a respective list of storage unit identifiers for identifying a respective group of storage units of the storage that are allocated to each of the clients.

4. The data processing system as claimed in claim 1, wherein the storage server contains lists of storage unit identifiers and a respective key protecting each list, and wherein each list is accessible only when said the respective key protecting said each list is included in a request for identification of storage units in the storage server.

5. The data processing system as claimed in claim 1, wherein the client has local storage containing a configuration file including, for each pseudo-disk instance, a list of storage unit identifiers of storage units configured into said each pseudo-disk instance, and a list of server IP addresses for accessing the storage units configured into said each pseudo-disk instance.

6. The data processing system as claimed in claim 1, wherein the client is programmed with a list of storage server IP addresses, and wherein the protocol stack of the client includes a configuration and fail-over layer between the network block services layer and the IP layer, the configuration and fail-over layer responding to a failure to communicate with a storage server IP address in the list of storage server IP addresses by re-establishing communication with an alternative storage server IP address in the list of storage server IP addresses.

7. The data processing system as claimed in claim 6, wherein the configuration and fail-over layer maintains a respective Transmission Control Protocol (TCP) connection between the client and the storage server for each of the pseudo-disk instances.

8. The data processing system as claimed in claim 6, wherein the data processing system includes a plurality of storage servers including a first storage server and a second storage server linked to the first storage server by a remote data facility for maintaining a duplicate copy of a storage unit in storage of the first storage server and in storage of the second storage server, and wherein the client is programmed with a respective list of storage server IP addresses for each pseudo-disk instance, and wherein the respective list of storage server IP addresses for at least one of the pseudo-disk instances includes an IP address for the first storage server and an IP address for the second storage server.

9. The data processing system as claimed in claim 1, wherein the block interface appears to the operating system or application program of the client as a device driver for each pseudo-disk instance.

10. The data processing system as claimed in claim 1,

wherein the IP packets transmitted over the IP network between the client and the server in accordance with the network block services protocol include client opcodes and server opcodes, the client opcodes include a READ opcode for reading a first specified length of data from a first specified storage unit beginning at a first specified offset in the first specified storage unit, a WRITE opcode for writing a second specified length of data to a second specified storage unit beginning at a second specified offset in the second specified storage unit, and an INFO opcode for requesting the identification of the storage units that are allocated to the client, and

wherein the server opcodes include a READ RETURN opcode for returning the first specified length of data requested by the READ opcode, a WRITE RETURN opcode for returning a confirmation of the writing of the second specified length of data as requested by the WRITE opcode, and an INFO RETURN opcode for returning the identification of the storage units that are allocated to the client.

11. The data processing system as claimed in claim 10, wherein the IP packets transmitted over the IP network between the client and the server in accordance with the network block services protocol further include at least one IP packet including the INFO opcode for requesting read capacity of a third specified storage unit.

12. The data processing system as claimed in claim 10, wherein the client opcodes further include a NO-OP opcode for requesting the server to return an IP packet, and wherein the server opcodes further include a NO-OP RETURN opcode for returning the IP packet requested by the NO-OP opcode.

13. The data processing system as claimed in claim 1, wherein each IP packet transmitted over the IP network between the client and the server in accordance with the network block services protocol includes a packet header having an opcode field, a packet data unit length field, a packet identifier field, a status field, a storage unit identifier field, an offset field, and a data length field.

14. A client for accessing a storage server in an Internet Protocol (IP) network, the storage server containing storage units allocated to the client, the storage server also containing an identification of the storage units allocated to the client, wherein the client is programmed for encoding and decoding IP packets transmitted over the IP network between the client and the server in accordance with a network block services protocol, the IP packets transmitted over the IP network between the client and the server in accordance with the network block services protocol including IP packets for requesting identification of the storage units allocated to the client, IP packets for reading data from the storage units allocated to the client, and IP packets for writing data to the storage units allocated to the client, the client being programmed for using the network block services protocol for obtaining the identification of the storage units allocated to the client, the client being programmed for configuring the storage units allocated to the client into local pseudo-disk instances, the client maintaining a list of storage server IP addresses for each of the local pseudo-disk instances, and the client being further programmed with a device driver for accessing each local pseudo-disk instances by establishing and maintaining a Transmission Control Protocol (TCP) connection to at least one storage server IP address in the list of storage server IP addresses for said each local pseudo-disk instance.

15. The client as claimed in claim 14, wherein the client is programmed with a protocol stack including a block interface layer of the device driver for interfacing with an operating system or application program of the client, a network block services layer of the device driver for managing the network block services protocol, a configuration and fail-over layer of the device driver for establishing and maintaining a TCP connection to at least one server IP address in each list, a TCP layer for managing the Transmission Control Protocol, and an IP layer for managing the Internet Protocol over the IP network.

16. The client as claimed in claim 14, wherein the client has local storage containing a configuration file including a properties list for each local pseudo-disk instance, the properties list including the list of storage server IP addresses and a respective list of storage unit identifiers associated with said each local pseudo-disk instance.

17. The client as claimed in claim 14, wherein the device driver includes a character and block device driver, a streams module having a read stream routine and a write stream routine, send queues, receive queues, and kernel thread instances including a respective kernel thread instance for each open TCP connection for the local pseudo-disk instances.

18. The client as claimed in claim 14,

wherein the IP packets transmitted over the IP network between the client and the server in accordance with the network block services protocol include client opcodes and server opcodes, the client opcodes include a READ opcode for reading a first specified length of data from a first specified storage unit beginning at a first specified offset in the first specified storage unit, a WRITE opcode for writing a second specified length of data to a second specified storage unit beginning at a second specified offset in the second specified storage unit, and an INFO opcode for requesting the identification of the storage units that are allocated to the client, and

wherein the server opcodes include a READ RETURN opcode for returning the first specified length of data requested by the READ opcode, a WRITE RETURN opcode for returning a confirmation of the writing of the second specified length of data as requested by the WRITE opcode, and an INFO RETURN opcode for returning the identification of the storage units that are allocated to the client.

19. The client as claimed in claim 18, wherein the IP packets transmitted over the IP network between the client and the server in accordance with the network block services protocol further include at least one IP packet including the INFO opcode for requesting read capacity of a third specified storage unit.

20. The client as claimed in claim 18, wherein the client opcodes further include a NO-OP opcode for requesting the server to return an IP packet, and wherein the server opcodes further include a NO-OP RETURN opcode for returning the IP packet requested by the NO-OP opcode.

21. The client as claimed in claim 14, wherein each IP packet transmitted over the IP network between the client and the server in accordance with the network block services protocol includes a packet header having an opcode field, a packet data unit length field, a packet identifier field, a status field, a storage unit identifier field, an offset field, and a data length field.

22. A storage server comprising storage for use in an Internet Protocol (IP) network linking clients to the storage server for client access to the storage, the storage including a respective group of storage units allocated to each client, the storage containing identification of the storage units allocated to said each client, the storage server being programmed to encode and decode IP packets transmitted over the IP network between said each client and the server in accordance with a network block services protocol, the IP packets transmitted over the IP network between said each client and the server in accordance with the network block services protocol including IP packets for requesting identification of the storage units allocated to said each client, IP packets for reading data from the storage units allocated to said each client, and IP packets for writing data to the storage units allocated to said each client.

23. The storage server as claimed in claim 22, wherein the storage units are logical volumes of the storage in the storage server.

24. The storage server as claimed in claim 22, wherein the storage of the storage server contains, for said client, a respective list of storage unit identifiers for identifying the respective group of storage units of the storage that are allocated to said each client.

25. The storage server as claimed in claim 22, wherein the storage of the storage server contains key-protected files of lists of allocated storage units, and wherein each IP packet for requesting identification of the storage units allocated to said each client must include a proper key for accessing one of the respective key-protected files in order for the storage server to return, to said each client, the storage unit identifiers of storage units allocated to said each client.

26. The storage server as claimed in claim 22,

wherein the IP packets transmitted over the IP network between said each client and the server in accordance with the network block services protocol include client opcodes and server opcodes, the client opcodes include a READ opcode for reading a first specified length of data from a first specified storage unit beginning at a first specified offset in the first specified storage unit, a WRITE opcode for writing a second specified length of data to a second specified storage unit beginning at a second specified offset in the second specified storage unit, and an INFO opcode for requesting the identification of the storage units that are allocated to said each client, and

wherein the server opcodes include a READ RETURN opcode for returning the first specified length of data requested by the READ opcode, a WRITE RETURN opcode for returning a confirmation of the writing of the second specified length of data as requested by the WRITE opcode, and an INFO RETURN opcode for returning the identification of the storage units that are allocated to said each client.

27. The storage server as claimed in claim 26, wherein the IP packets transmitted over the IP network between said each client and the server in accordance with the network block services protocol further include at least one IP packet including the INFO opcode for requesting read capacity of a third specified storage unit.

28. The storage server as claimed in claim 26, wherein the client opcodes further include a NO-OP opcode for requesting the server to return an IP packet, and wherein the server opcodes further include a NO-OP RETURN opcode for returning the IP packet requested by the NO-OP opcode.

29. The storage server as claimed in claim 22, wherein each IP packet transmitted over the IP network between said each client and the server in accordance with the network block services protocol includes a packet header having an opcode field, a packet data unit length field, a packet identifier field, a status field, a storage unit identifier field, an offset field, and a data length field.

30. A client driver for use in a client having at least one IP port for accessing network-attached storage allocated to the client in an Internet Protocol (IP) network, the client driver including:

configuration file means for storing, in local storage of the client, configuration information defining pseudo-disk instances configured from the network-attached storage allocated to the client and identifying server IP addresses at which the network-attached storage of the pseudo-disk instances may be accessed;

network block services means for encoding and decoding IP packets transmitted over the IP network between the client and the network-attached storage in accordance with a network block services protocol, the IP packets transmitted over the IP network between the client and the network-attached storage in accordance with the network block services protocol including IP packets for requesting identification of the network-attached storage allocated to the client, IP packets for reading data from the network-attached storage allocated to the client, and IP packets for writing data to the network-attached storage allocated to the client;

configuration and fail-over means coupled to the network block services means and the IP port and accessing the configuration file for using the network block services means for discovering the network-attached storage allocated to the client and configuring the pseudo disk instances from the network-attached storage allocated to the client, and for establishing and maintaining a Transmission Control Protocol (TCP) connection for an open pseudo-disk instance to at least one storage server IP address at which network-attached storage of the open pseudo-disk instance may be accessed; and

block device driver means coupled to the network block services means and the configuration and fail-over means for presenting a disk driver interface to client programs for access to the pseudo-disk instances.

31. The client driver as claimed in claim 30, wherein each IP packet transmitted over the IP network between the client and the network-attached storage in accordance with the network block services protocol includes a packet header having an opcode field, a packet data unit length field, a packet identifier field, a status field, a storage unit identifier field, an offset field, and a data length field.

32. A method of operating a client to access a storage server in an Internet Protocol (IP) network, the storage server containing storage units allocated to the client, the storage server also containing an identification of the storage units allocated to the client, said method including the client encoding and decoding IP packets transmitted over the IP network between the client and the server in accordance with a network block services protocol, the IP packets transmitted over the IP network between the client and the server in accordance with the network block services protocol include IP packets for requesting identification of the storage units allocated to the client, IP packets for reading data from the storage units allocated to the client, and IP packets for writing data to the storage units allocated to the client, and the client obtains from the storage server the identification of the storage units allocated to the client and configures the identified storage units allocated to the client into local pseudo-disk instances, and maintains a respective list of server IP addresses for each of the local pseudo-disk instances, and the client operates a device driver that accesses each local pseudo-disk instance by establishing and maintaining a Transmission Control Protocol (TCP) connection to at least one server IP address in the list of server IP addresses for said each local pseudo-disk instance.

33. The method as claimed in claim 32, wherein the client has local storage, and the method includes the client maintaining a configuration file in the local storage, the configuration file including a properties list for each local pseudo-disk instance, the properties list including the list of server IP addresses and a respective list of storage unit identifiers associated with each local pseudo-disk instance.

34. The method as claimed in claim 32,

wherein the IP packets transmitted over the IP network between the client and the server in accordance with the network block services protocol include client opcodes and server opcodes, the client opcodes include a READ opcode for reading a first specified length of data from a first specified storage unit beginning at a first specified offset in the first specified storage unit, a WRITE opcode for writing a second specified length of data to a second specified storage unit beginning at a second specified offset in the second specified storage unit, and an INFO opcode for requesting the identification of the storage units that are allocated to the client, and

wherein the server opcodes include a READ RETURN opcode for returning the first specified length of data requested by the READ opcode, a WRITE RETURN opcode for returning a confirmation of the writing of the second specified length of data as requested by the WRITE opcode, and an INFO RETURN opcode for returning the identification of the storage units that are allocated to the client.

35. The method as claimed in claim 34, wherein the IP packets transmitted over the IP network between the client and the server in accordance with the network block services protocol further include at least one IP packet including the INFO opcode for requesting read capacity of a third specified storage unit.

36. The method as claimed in claim 34, wherein the client opcodes further include a NO-OP opcode for requesting the server to return an IP packet, and wherein the server opcodes further include a NO-OP RETURN opcode for returning the IP packet requested by the NO-OP opcode.

37. The method as claimed in claim 32, wherein each IP packet transmitted over the IP network between the client and the server in accordance with the network block services protocol includes a packet header having an opcode field, a packet data unit length field, a packet identifier field, a status field, a storage unit identifier field, an offset field, and a data length field.