Reducing network traffic for remote file system accesses by keeping track of unallocated regions in files

• US 6,516,344 B1
• Filed: 11/08/1999
• Issued: 02/04/2003
• Est. Priority Date: 11/08/1999
• Status: Active Grant

• Current Assignee: Oracle America, Inc. (Oracle Corporation)
• Original Assignee: Sun Microsystems Incorporated (Oracle Corporation)
• Inventors: Nazari, Siamak
• Primary Examiner(s): Meky, Moustafa M.
• Assistant Examiner(s): PARTON, KEVIN S
• Application Number:
  US09/436,050
• Time in Patent Office: 1,184 Days
• Field of Search: 709/217, 709/203, 709/232, 709/216, 709/218, 709/219, 709/231, 709/205, 709/206, 709/10
• US Class Current: 709/217
• CPC Class Codes: G06F 16/10 File systems; File servers
• CPC Class Codes: Y10S 707/99953 Recoverability

Abstract

A system for reducing network traffic for remote file system accesses receives requests at a local computer system for access to a file on the remote server. If the request is a read operation, and the operation is directed to an unallocated region of the file on the remote server, the system returns a block of null values to the requestor without receiving the block of null values from the remote server. Otherwise, the system sends a request to the remote server to read from the file. If the request is a write operation, and the operation is directed to an unallocated region of the file on the remote server, the system sends a request to the remote server to allocate storage for the write operation. Next, the system writes the data into a local cache. Later, the system copies the data from the cache to the remote storage.

Claims

1. A method for reducing network traffic for remote file system accesses by sending information specifying unallocated regions within a file from a server to a remote client, the method comprising:

receiving, at the server, an access to a file residing in storage on the server;

if the access is a read operation to read data from the file, determining whether the read operation is directed to a region of the file that is presently unallocated in the storage;

if the read operation is directed to the region of the file that is presently unallocated, sending information to the remote client specifying regions of the file that have not been allocated in the storage; and

if the read operation is directed to the region of the file that is presently allocated,

reading the data from the file in the storage, and

sending the data to the remote client.

2. The method of claim 1, wherein if the access is a write operation and the write operation is directed to a region of the file that is presently unallocated in the storage on the server, the method further comprises,

allocating storage for the write operation in the storage on the server; and

waiting for the data to be sent from the remote client.

3. The method of claim 1, further comprising configuring the file for random accesses prior to receiving the access.

4. The method of claim 1, wherein the file resides in nonvolatile storage on the remote server.

5. A apparatus that reduces network traffic for remote file system accesses by sending information specifying unallocated regions within a file from a server to a remote client, the apparatus comprising:

the server;

a storage within the server;

a receiving mechanism within the server that receives an access to a file residing in the nonvolatile storage; and

a read operation processing mechanism within the server for reading data, the read operation processing mechanism being configured to,

determine whether the read operation is directed to a region of the file that is presently unallocated in the nonvolatile storage, and

send information to the remote client specifying regions of the file that have not been allocated in the nonvolatile storage if the read operation is directed to a region of the file that is presently unallocated.

6. The apparatus of claim 5, wherein the read operation processing mechanism is further configured to send the data from the file to the remote client if the read operation is directed to the region of the file that is presently allocated.

7. The apparatus of claim 5, further comprising a write operation processing mechanism for writing data that is configured to,

allocate storage for the write operation in the nonvolatile storage on the server; and

wait for the data to be sent from the remote client.

8. The apparatus of claim 5, further comprising a mechanism that configures the file for random accesses.

9. The apparatus of claim 5, wherein the storage within the server includes a nonvolatile storage.

10. A computer readable storage medium storing instructions that when executed by a computer cause the computer to perform a method for reducing network traffic for remote file system accesses by sending information specifying unallocated regions within a file from a server to a remote client, the method comprising:

receiving, at the server, an access to a file residing in a storage on the server;

if the access is a read operation to read data from the file, determining whether the read operation is directed to a region of the file that is presently unallocated in the storage;

if the read operation is directed to the region of the file that is presently unallocated, sending information to the remote client specifying regions of the file that have not been allocated in the storage; and

if the read operation is directed to the region of the file that is presently allocated, and

reading the data from the file in the storage.

11. The computer readable storage medium of claim 10, wherein if the access is a write operation, and the write operation is directed to a region of the file that is presently unallocated in the storage on the server, further comprising,

allocating storage for the write operation in the storage on the server; and

waiting for the data to be sent from the remote client.