Multi-protocol sharable virtual storage objects

• US 7,953,819 B2
• Filed: 08/22/2003
• Issued: 05/31/2011
• Est. Priority Date: 08/22/2003
• Status: Active Grant

• Current Assignee: Emc IP Holding Company LLC (Dell Technologies Inc.)
• Original Assignee: EMC Corporation (Dell Technologies Inc.)
• Inventors: Liang, Rui, Ku, Mark K, Zheng, Jiannan, Faibish, Sorin, Jiang, Xiaoye
• Primary Examiner(s): LIN, WEN TAI
• Application Number:
  US10/646,851
• Publication Number:
  US 20050044162A1
• Time in Patent Office: 2,839 Days
• Field of Search: 707/204, 709/202, 709/212
• US Class Current: 709/219
• CPC Class Codes: G06F 16/10 File systems; File servers
• CPC Class Codes: H04L 67/1095 Replication or mirroring of data, e.g. scheduling or transport for data synchronisation between network nodes
• 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 69/329 in the application layer [OSI layer 7]
• CPC Class Codes: H04L 9/40 Network security protocols

Abstract

A storage object such as a virtual disk drive or a raw logical volume is contained in a UNIX compatible file so that the file containing the storage object can be exported using the NFS or CIFS protocol and shared among UNIX and MS Windows clients or servers. The storage object can be replicated and backed up using conventional file replication and backup facilities without disruption of client access to the storage object. For client access to data of the storage object, a software driver accesses the file containing the storage object. For example, a software driver called a virtual SCSI termination is used to access a file containing a virtual SCSI disk drive. Standard storage services use the SCSI over IP protocol to access the virtual SCSI termination. An IP replication or snapshot copy facility may access the file containing the virtual SCSI disk drive using a higher-level protocol.

Claims

1. In a data processing network including a client, a first file server, and a second file server, a method of access to a storage object in the first file server, said method comprising:

the client using a block level access protocol over the network to access the storage object in the first file server; and

the first file server accessing the storage object in the first file server by accessing a file in the first file server containing data of the storage object;

which includes the first file server replicating a snapshot copy of the file from the first file server over the network to the second file server concurrent with the client using the block level access protocol over the network to write data to the storage object in the first file server;

wherein the network is an IP network, the client uses the block level access protocol over a first TCP/IP connection over the network to access the storage object in the first file server, and the client initiates the step of the first file server replicating the snapshot copy of the file over the network to the second file server by sending a command over a second TCP/IP connection to the first file server; and

which includes the client pausing the step of writing of data to the storage object in the first file server after a commit operation, and during the pause, the client performing the step of initiating the step of the first file server replicating the snapshot copy of the file from the first file server over the network to the second file server by sending the command over the second TCP/IP connection.

2. The method as claimed in claim 1, wherein the first TCP/IP connection is concurrent with the second TCP/IP connection.

3. The method as claimed in claim 1, which includes the first file server also providing access to the storage object in the first file server over the network by means of a file access protocol over the network, the file access protocol accessing the file in the first file server containing the data of the storage object in the first file server.

4. The method as claimed in claim 3, wherein the file access protocol is the Network File System (NFS) protocol.

5. The method as claimed in claim 3, wherein the file access protocol is the Common Internet File System (CIFS) protocol.

6. In a data processing network including a client, a first file server, and a second file server, a method of access to a virtual direct access storage device in the first file server, attributes and data of the virtual direct access storage device being stored in at least one file in the first file server, said method comprising:

the client using a block level access protocol over the network to access the virtual direct access storage device in the first file server, the first file server responding to commands in accordance with the block level access protocol for access to the virtual direct access storage device in the first file server by accessing the attributes and data of the virtual direct access storage device in the first file server; and

the first file server providing access over the network to the virtual block storage device in the first file server in accordance with a file access protocol by accessing said at least one file in the first file server;

which includes the first file server replicating a snapshot copy of said at least one file from the first file server over the network to the second file server concurrent with the client using the block level access protocol over the network to write new data to the virtual direct access storage device in the first file server;

wherein the network is an IP network, the client uses the block level access protocol over a first TCP/IP connection over the network to the first file server to access the virtual direct access storage device in the first file server, and the client initiates the step of the first file server replicating the snapshot copy of said at least one file by sending a command over a second TCP/IP connection to the first file server; and

which includes the client pausing the writing of the new data to the virtual direct access storage device in the first file server after a commit operation, and during the pause, the client performs the step of initiating the step of the first file server replicating snapshot copy of said at least one file by sending the command over the second TCP/IP connection to the first file server.

7. The method as claimed in claim 6, wherein the first TCP/IP connection is concurrent with the second TCP/IP connection.

8. The method as claimed in claim 6, wherein the network is an IP network, and the block level access protocol is the Small Computer System Interface (SCSI) protocol.

9. The method as claimed in claim 6, wherein the file access protocol is the Network File System (NFS) protocol.

10. The method as claimed in claim 6, wherein the file access protocol is the Common Internet File System (CIFS) protocol.