System and method for reliably storing data and providing efficient incremental backup and asynchronous mirroring by preferentially handling new data

1. A method for reliably storing data in a computer system, comprising:

receiving a piece of data to be stored at a storage system:

writing a first copy of the data to the storage system according to a first data redundancy scheme;

writing a second copy of the data to the storage system according to a second data redundancy scheme;

maintaining metadata of the data written to the storage system according to the second data redundancy scheme;

copying the data written to the storage system according to the second data redundancy scheme to a backup storage system, wherein the copying is performed in response to a defined condition being met; and

removing the data written to the storage system according to the second data redundancy scheme after it has been copied to the backup storage system,

wherein the stored data includes both blocks of user data and attributes such as file names that are associated with collections of user data, and

wherein the metadata is maintained by using a skeleton file system that replicates all the namespace and attribute information of the stored data and a set of delta files each of which records all the data updates that have been made to a corresponding file and that have not been copied to the backup storage system.

2. A method for reliably storing data in a computer system, comprising:

receiving a piece of data to be stored at a storage system;

writing a first copy of the data to the storage system according to a first data redundancy scheme;

writing a second copy of the data to the storage system according to a second data redundancy scheme;

maintaining metadata of the data written to the storage system according to the second data redundancy scheme;

copying the data written to the storage system according to the second data redundancy scheme to a backup storage system, wherein the copying is performed in response to a defined condition being met; and

removing the data written to the storage system according to the second data redundancy scheme after it has been copied to the backup storage system,

wherein the method further comprises recognizing a failure in the storage system which compromises the reliability of the data stored according to the first data redundancy scheme, and

wherein rebuilding an accurate copy of the data stored according to the first data redundancy scheme comprises utilizing the maintained metadata as a blueprint for combining data retrieved from the backup storage system and data remaining in the store system.

3. The method of claim 2 wherein data remaining in the storage system comprises data stored according to the second data redundancy scheme.

4. A disaster recovery system, comprising:

a plurality of disks;

a storage controller attached to the disks, wherein the storage controller receives data to be stored on the plurality of physical disks;

first data redundancy scheme logic included within the storage controller for writing a copy of the data received by the storage controller to the physical disks according to a first data redundancy scheme;

second data redundancy scheme logic included within the storage controller for writing a second copy of the data received by the storage controller to the physical disks according to a second data redundancy scheme;

metadata of the data written to the storage system according to the second data redundancy scheme;

data backup logic to copy the data written to the storage system according to the second data redundancy scheme to a backup storage system, wherein the copying is performed in response to a defined condition being met; and

maintenance logic to remove the data written to the storage system according to the second data redundancy scheme after it has been copied to the backup storage system,

wherein the stored data includes both blocks of user data and attributes such as file names that are associated with collections of blocks of user data,

wherein the metadata is maintained by using a skeleton file system that replicates all the namespace and attribute information of the stored data and a set of delta files each of which records all the data updates that have been made to a corresponding file and that have not been copied to the backup storage system.

5. A disaster recovery system, comprising:

a plurality of disks;

a storage controller attached to the disks, wherein the storage controller receives data to be stored on the plurality of physical disks;

first data redundancy scheme logic included within the storage controller for writing a copy of the data received by the storage controller to the physical disks according to a first data redundancy scheme;

second data redundancy scheme logic included within the storage controller for writing a second copy of the data received by the storage controller to the physical disks according to a second data redundancy scheme;

metadata of the data written to the storage system according to the second data redundancy scheme;

data backup logic to copy the data written to the storage system according to the second data redundancy scheme to a backup storage system, wherein the copying is performed in response to a defined condition being met; and

maintenance logic to remove the data written to the storage system according to the second data redundancy scheme after it has been copied to the backup storage system,

wherein the system further comprises monitoring logic to recognize a failure in the storage system which compromises the reliability of the data stored according to the first data redundancy scheme;

wherein the system further comprises responding to the failure by rebuilding an accurate copy of the data stored according to the first data redundancy scheme, and

wherein rebuilding an accurate copy of the data stored according to the first data redundancy scheme comprises, utilizing the maintained metadata as a blueprint for combining data retrieved from the backup storage system and data remaining in the storage system.

6. The system of claim 5 wherein data remaining in the storage system comprises data stored according to the second data redundancy scheme.

7. A method for deploying a disaster recovery service in a computer system, comprising:

integrating computer readable code into a system for receiving a piece of data to be stored at a storage system;

integrating computer readable code into a system for writing a first copy of the data to the storage system according to a first data redundancy scheme;

integrating computer readable code into a system for writing a second copy of the data to the storage system according to a second data redundancy scheme;

integrating computer readable code into a system for maintaining metadata of the data written to the storage system according to the second data redundancy scheme;

integrating computer readable code into a system for copying the data written to the storage system according to the second data redundancy scheme to a backup storage system, wherein the copying is performed in response to a defined condition being met; and

integrating computer readable code into a system for removing the data written to the storage system according to the second data redundancy scheme after it has been copied to the backup storage system,

wherein the stored data includes both blocks of user data and attributes such as file names that are associated with collections of blocks of user data, and

wherein the metadata is maintained by using a skeleton file system that replicates all the namespace and attribute information of the stored data and a set of delta files each of which records all the data updates that have been made to a corresponding file and that have not been copied to the backup storage system.

8. A method for deploying a disaster recovery service in a computer system, comprising:

integrating computer readable code into a system for receiving a piece of data to be stored at a storage system;

integrating computer readable code into a system for writing a first copy of the data to the storage system according to a first data redundancy scheme;

integrating computer readable code into a system for writing a second copy of he data to the storage system according to a second data redundancy scheme;

integrating computer readable code into a system for maintaining metadata of the data written to the storage system according to the second data redundancy scheme;

integrating computer readable code into a system for copying the data written to the storage system according to the second data redundancy scheme to a backup storage system, wherein the copying is performed in response to a defined condition being met; and

integrating computer readable code into a system for removing the data written to the storage system according to the second data redundancy scheme after it has been copied to the backup storage system,

method further comprising integrating computer readable code for recognizing a failure in the storage system which compromises the reliability of the data stored according to the first data redundancy scheme, and

wherein rebuilding an accurate copy of the data stored according to the first data redundancy scheme comprises utilizing the maintained metadata as a blueprint for combining data retrieved from the backup storage system and data remaining in the storage system.

9. The method of claim 8 wherein data remaining in the storage system comprises data stored according to the second data redundancy scheme.