Method and system for data replication

• US 20070124659A1
• Filed: 05/15/2006
• Published: 05/31/2007
• Est. Priority Date: 11/04/2005
• Status: Active Grant

• Current Assignee: Oracle America, Inc. (Oracle Corporation)
• Original Assignee: Sun Microsystems Incorporated (Oracle Corporation)
• Inventors: Ahrens, Matthew, Moore, William, Bonwick, Jeffrey
• Granted Patent: US 7,596,739 B2
• Time in Patent Office: Days
• US Class Current: 714/800
• CPC Class Codes: G06F 11/1076 Parity data used in redundant arrays of independent storages, e.g. in RAID systems
• CPC Class Codes: G06F 2211/1059 Parity-single bit-RAID5, i.e. RAID 5 implementations

Abstract

A method for writing data to a storage pool includes receiving a write operation to write a logical block of data to the storage pool, determining a number (n−1) of physical blocks required to store the logical block of data, generating a parity block using the logical block of data, allocating n physical blocks in the storage pool, writing the parity block in the first of n allocated physical block, and writing the logical block of data across the remaining n−1 allocated physical blocks, where n is less than a number of disks in the storage pool, and where each of the n allocated physical blocks is located on a different disk in the storage pool.

Claims

1. A method for writing data to a storage pool, comprising:

receiving a write operation to write a logical block of data to the storage pool;

determining a number (n−

1) of physical blocks required to store the logical block of data;

generating a parity block using the logical block of data;

allocating n physical blocks in the storage pool;

writing the parity block in the first of n allocated physical block; and

writing the logical block of data across the remaining n−

1 allocated physical blocks,

wherein n is less than a number of disks in the storage pool, and

wherein each of the n allocated physical blocks is located on a different disk in the storage pool.

2. The method of claim 1, wherein the logical block is an indirect block.

3. The method of claim 1, wherein a size of the logical block is stored in a pointer referencing the logical block.

4. The method of claim 1, wherein the logical block is associated with a file in the file system.

5. A method for writing data to a storage pool, comprising:

receiving a write operation to write a logical block of data to the storage pool;

determining a number (n) of physical blocks required to store the logical block of data;

dividing the logical block of data into n blocks;

generating a first parity block using d−

1 blocks, wherein d corresponds to a number of disks in the storage pool;

generating a second parity block using n-d+1 blocks, wherein the n-d+1 blocks were not used to generate the first parity block;

allocating n+2 physical blocks in the storage pool;

writing the first parity block and the second parity block to a first of d disks in the storage pool; and

writing the n blocks across the remaining d−

1 in the storage pool,

wherein at most two of the n blocks is written to any of the d−

1 disks in the storage pool, and

wherein d is less than n+2.

6. The method of claim 5, wherein the logical block is an indirect block.

7. The method of claim 5, wherein a size of the logical block is stored in a pointer referencing the logical block.

8. The method of claim 5, wherein the logical block is associated with a file in the file system.

9. A system, comprising:

a storage pool comprising a number of disks (d); and

a file system comprising functionality to;

receive a write operation to write a logical block of data to the storage pool;

determine a number (n−

1) of physical blocks required to store the logical block of data;

generate a parity block using the logical block of data;

allocate n physical blocks in the storage pool;

write the parity block in the first of n allocated physical block; and

write the logical block of data across the remaining n−

1 allocated physical blocks,

wherein n is less than d, and

wherein each of the n allocated physical blocks is located on a different disk in the storage pool.

10. The system of claim 9, wherein the logical block is an indirect block.

11. The system of claim 9, wherein a size of the logical block is stored in a pointer referencing the logical block.

12. The system of claim 9, wherein the logical block is associated with a file in the file system.