Method and apparatus for storing and retrieving multiple point-in-time consistent data sets

A method of processing multiple point-in-time consistent data sets comprising:

• creating a first data set;
• creating a second data set wherein the first data set and the second data set are associated with a backup appliance having memory and which is associated with backup storage;
• transferring a first update from a primary storage controller to the backup appliance;
• determining that the first update affects first data stored in the backup storage that has been unchanged since following the creation of the first data set and the second data set;
• reading the first data from the backup storage;
• storing a copy of the first data to a memory location independent of the first and second data sets;
• saving a pointer associated with each of the first data set and the second data set and directed to the copy of the first data;
• and
• applying the update to the first data on the backup storage.

A backup appliance associated with backup storage, the backup appliance having the capability to receive data updates from a primary storage controller and the backup appliance comprising:

• means for creating a first data set;
• means for creating a second data set;
• means for determining whether a data update affects data that has been unchanged following the creation of the first data set and the second data set;
• means for reading the first data from the backup storage;
• means for writing a copy of the first data to a storage location associated with one of the first data set, the second data set and a memory location independent of the first and second data sets;
• means for saving a pointer associated with one of the first data set and the second data set and directed to the copy of the first data;
• and
• means for applying the update to the first data on the backup storage.

An article of manufacture for use in programming a backup device to process multiple point-in-time consistent data sets, the article of manufacture comprising instructions for:

• creating a first data set;
• creating a second data set wherein the first data set and the second data set are associated with a backup appliance which is associated with backup storage;
• transferring a first update from a primary storage controller to the backup appliance;
• determining that the first update affects first data stored in the backup storage that has been unchanged following the creation of the first data set and the second data set;
• reading the first data from the backup storage;
• writing a copy of the first data to the first data set;
• saving a pointer associated with the second data set and directed to the copy of the first data;
• and
• applying the update to the first data on the backup storage.

An article of manufacture for use in programming a backup device to process multiple point-in-time consistent data sets, the article of manufacture comprising instructions for:

• creating a first data set;
• creating a second data set wherein the first data set and the second data set are associated with a backup appliance having memory and which is associated with backup storage;
• transferring a first update from a primary storage controller to the backup appliance;
• determining that the first update affects first data stored in the backup storage that has been unchanged since following the creation of the first data set and the second data set;
• reading the first data from the backup storage;
• storing a copy of the first data to a memory location independent of the first and second data sets;
• saving a pointer associated with each of the first data set and the second data set and directed to the copy of the first data;
• and
• applying the update to the first data on the backup storage.