Storing lossy hashes of file names and parent handles rather than full names using a compact table for network-attached-storage (NAS)

• US 8,447,762 B2
• Filed: 08/14/2007
• Issued: 05/21/2013
• Est. Priority Date: 03/04/2004
• Status: Active Grant

• Current Assignee: Cufer Asset Ltd LLC (Intellectual Ventures LLC)
• Original Assignee: Sanwork Data Mgmt LLC (Intellectual Ventures LLC)
• Inventors: Brendel, Juergen
• Primary Examiner(s): Lee, Wilson
• Application Number:
  US11/838,628
• Publication Number:
  US 20070277227A1
• Time in Patent Office: 2,107 Days
• Field of Search: 707 1- 10, 707200-203, 707713-718, 707736-738, 707754-770, 707781-788, 709200-203, 709/214, 709/229
• US Class Current: 707/736
• CPC Class Codes: G06F 16/13 File access structures, e.g. distributed indices arrangements of input from, or output to, record carriers G06F3/06
• CPC Class Codes: G06F 16/1824 implemented using Network-attached Storage [NAS] architecture distributed or networked storage systems G06F3/067; protocols for distributed storage of data in a network H04L67/1097

Abstract

Multiple Network Attached Storage (NAS) appliances are pooled together by a virtual NAS translator, forming one common name space visible to clients. Clients send messages to the virtual NAS translator with a file name and a virtual handle of the parent directory that are concatenated to a full file-path name and compressed by a cryptographic hash function to generate a hashed-name key. The hashed-name key is matched to a storage key in a table. The full file-path name is not stored, reducing the table size. A unique entry number is returned to the client as the virtual file handle that is also stored in another table with one or more native file handles, allowing virtual handles to be translated to native handles that the NAS appliance servers use to retrieve files. File movement among NAS servers alters native file handles but not virtual handles, hiding NAS details from clients.

Claims

1. A method for accessing files, the method comprising:

receiving from a network, by a file system apparatus, a file-access request from a client, wherein the file-access request contains a virtual file handle;

extracting, by the file system apparatus, a client unique identifier from the virtual file handle, wherein prior to receiving the file-access request from the client, receiving a file-opening request that contains a file name and a parent-directory virtual file handle and combining, by the file system apparatus, the file name and the parent-directory virtual file handle into a combination name for use in generating and providing the client unique identifier to the client for inclusion in the virtual file handle of the file access request;

searching, by the file system apparatus, a first table of file translation entries for a matching entry that matches the client unique identifier;

reading, by the file system apparatus, a server identifier from the matching entry;

obtaining, by the file system apparatus, a native file handle using the server identifier and the file-access request from the client;

replacing, by the file system apparatus, the virtual file handle in the file-access request with the native file handle to generate a translated file-access request; and

sending, by the file system apparatus, the translated file-access request over the network to a selected one of a plurality of storage apparatuses.

2. The method of claim 1 wherein receiving the file-access request includes receiving the file-access request over a network that carries Transport-Control-Protocol/Internet Protocol (TCP/IP) packets;

wherein the file-access request and the translated file-access request are messages for a network-file-system (NFS) or a Common-Internet-File-System (CIFS) protocol layer on the selected server and on the client.

3. The method of claim 1, further comprising:

compressing, by the file system apparatus, the combination name with a cryptographic hash function to generate a hashed-name key;

searching, by the file system apparatus, the first table for the matching entry that has a storage key that matches the hashed-name key; and

reading, by the file system apparatus, the unique identifier from the matching entry.

4. The method of claim 3, further comprising:

generating, by the file system apparatus, the virtual file handle that includes the unique identifier;

sending, by the file system apparatus, the virtual file handle back to the client over the network in response to the file-opening request.

5. The method of claim 3, wherein reading the unique identifier includes reading a unique identifier generated by an 8-byte up or down counter.

6. The method of claim 1, further comprising replacing by the file system apparatus, the virtual file handle with a different native file handle in response to a moving of data from the selected server.

7. A method for accessing files, comprising:

receiving from a file system apparatus, via a network, by a storage apparatus, a translated file-access request of a client device, wherein the translated file-access request includes a native file handle determined based on a virtual file handle having a client unique identifier and included in a file-access request of the client device, wherein a file-opening request including a file name and parent-directory virtual file handle have been combined into a combination name prior to the translated file-access request being received by the storage apparatus for use in generating and providing the client unique identifier to the client device for inclusion in the virtual file handle of the file access request;

accessing a selected file stored on the storage apparatus, by the storage apparatus, using the native file handle; and

sending the accessed file back to the client device, via the network, by the storage apparatus.

8. The method of claim 7, wherein accessing includes accessing a disk of the storage apparatus via a small-computer system interface (SCSI) controller.

9. The method of claim 7, wherein accessing includes accessing a redundant data storage of the storage apparatus via a Redundant Array of Independent Disks (RAID) controller.

10. An article of manufacture comprising:

a non-transitory tangible storage medium; and

a plurality of instructions stored thereon, and configured to cause an apparatus, in response to execution of the instructions by the apparatus, to perform operations including;

receiving from a network, a file-access request from a client device that contains a virtual file handle;

extracting a client unique identifier from the virtual file handle, wherein prior to receiving the file-access request from the client device, receiving a file-opening request from the client device that contains a file name and a parent-directory virtual file handle and combining the file name and the parent-directory virtual file handle into a combination name for use in generating and providing the client unique identifier to the client device for inclusion in the virtual file handle of the file access request;

searching a first table for a matching entry that matches the client unique identifier;

reading a server identifier from the matching entry;

obtaining a native file handle using the server identifier and the file-access request;

replacing the virtual file handle in the file-access request with the native file handle to generate a translated file-access request; and

sending the translated file-access request over the network to one of a plurality of storage devices.

11. An article of manufacture comprising:

a non-transitory tangible storage medium; and

a plurality of instructions stored thereon, and configured to cause a storage apparatus, in response to execution of the instructions by the storage apparatus, to perform operations including;

receiving from a file system apparatus, via a network, a translated file-access request of a client device, wherein the translated file-access request includes a native file handle determined based on a virtual file handle including a client unique identifier and included in a file-access request of the client device, wherein a file-opening request including a file name and parent-directory virtual file handle have been combined into a combination name prior to the translated file-access request being received by the storage apparatus for use in generating and providing the client unique identifier to the client device for inclusion in the virtual file handle of the file access request;

accessing a selected file stored on the storage apparatus, using the native file handle; and

sending the accessed file back to the client device, via the network.