Managing structured data in a data storage system

An information management system comprising:

• one or more computer processors configured to:
• at a first time, access data blocks in one or more database files in primary storage and combine the data blocks into data extents for storage in one or more secondary storage devices, each data extent stored in the one or more secondary storage devices is larger in size than a single data block stored in primary storage;
• determine data extent size based at least in part on whether the data blocks are stored in primary storage in contiguous memory space;
• maintain an extent table structure that maps metadata stored in primary memory into metadata extents stored in the one or more secondary storage devices, wherein the metadata extents are stored separately from the data extents, each metadata extent in the extent table structure comprising at least metadata and a location of each metadata extent in the one or more secondary storage devices;
• at a second time occurring after the first time, identify changed metadata in the primary storage where associated data blocks in the one or more database files remain unchanged, and map the changed metadata to the metadata extents in the one or more secondary storage devices;
• and
• update the metadata extents in the one or more secondary storage devices with the changed metadata without updating data extents associated with the changed metadata.

A method of protecting data in an information management system, the method comprising:

• accessing with one or more computer processors at a first time, data blocks in one or more database files in primary storage and combining the data blocks into data extents for storage in one or more secondary storage devices, each data extent stored in the one or more secondary storage devices is larger in size than a single data block stored in primary storage;
• determining data extent size based at least in part on whether the data blocks are stored in primary storage in contiguous memory space;
• maintaining an extent table structure that maps metadata stored in primary memory into metadata extents stored in the one or more secondary storage devices, wherein the metadata extents are stored separately from the data extents, each metadata extent in the extent table structure comprising at least metadata and a location of each metadata extent in the one or more secondary storage devices;
• identifying, at a second time occurring after the first time, changed metadata in the primary storage where associated data blocks in the one or more database files remain unchanged, and mapping the changed metadata to the metadata extents in the one or more secondary storage devices;
• and
• updating the metadata extents in the one or more secondary storage devices with the changed metadata without updating data extents associated with the changed metadata.