Multiple concurrent active file systems

A method for operating a data storage system, comprising:

• maintaining an original active file system to hold incoming write transactions;
• writing data at a selected time to blocks in a data storage device of the original active file system, the data written to blocks which do not hold old data of the data storage system;
• writing pointers to data of the original active file system at the selected time to the data storage device, the pointers written to blocks which do not hold old data of the data storage system, the pointers and a previously saved data of the active file system forming a consistency point of the original active file system at the selected time;
• starting a new active file system using the consistency point of the original active file system at the selected time;
• saving a change to the original active file system after the selected time without affecting the new active file system;
• and
• saving a change to the new active file system after the selected time without affecting the original active file system.

A data storage system apparatus, comprising:

• an original active file system to hold incoming write transactions;
• a data written at a selected time to blocks in a data storage device of the original active file system, the data written to blocks which do not hold old data of the data storage system;
• pointers written to data of the original active file system at the selected time to the data storage device, the pointers written to blocks which do not hold old data of the data storage system, the pointers and a previously saved data of the active file system forming a consistency point of the original active file system at the selected time;
• and
• a new active file system started using the consistency point of the original active file system at the selected time.

An apparatus for operating a data storage system, comprising:

• maintaining an original active file system to hold incoming write transactions;
• writing data at a selected time to blocks in a data storage device of the original active file system, the data written to blocks which do not hold old data of the data storage system;
• writing pointers to data of the original active file system at the selected time to the data storage device, the pointers written to blocks which do not hold old data of the data storage system, the pointers and a previously saved data of the active file system forming a consistency point of the original active file system at the selected time;
• starting a new active file system using the consistency point of the original active file system at the selected time;
• saving a change to the original active file system after the selected time without affecting the new active file system;
• and
• saving a change to the new active file system after the selected time without affecting the original active file system.

A computer readable storage media, comprising:

• said computer readable storage media containing program instructions for execution on a processor for a method of operating a data storage system, the program instructions for,
• maintaining an original active file system to hold incoming write transactions;
• writing data at a selected time to blocks in a data storage device of the original active file system, the data written to blocks which do not hold old data of the data storage system;
• writing pointers to data of the original active file system at the selected time to the data storage device, the pointers written to blocks which do not hold old data of the data storage system, the pointers and a previously saved data of the active file system forming a consistency point of the original active file system at the selected time;
• and
• starting a new active file system using the consistency point of the original active file system at the selected time.