Chunks

A chunk is the largest unit of physical disk dedicated to database server data storage. Chunks provide administrators with a significantly large unit for allocating disk space. The maximum size of an individual chunk is 4 terabytes. The number of allowable chunks is 32,766. You must run onmode -BC to enable the maximum size of a chunk and the maximum number allowable. If onmode -BC is not run, then the maximum chunk size is 2 gigabytes.

The database server administrator adds one or more chunks to the following storage spaces when they approach full capacity:

• Dbspace (see page Dbspaces)
• Blobspace (see page Blobspaces)
• Sbspace (see page Sbspaces)

For information on chunk names, size, and number, see Specifying Names for Storage Spaces and Chunks and Specifying the Maximum Size of Chunks.

The database server also uses chunks for mirroring. A primary chunk is a chunk from which the database server copies data to a mirror chunk. If the primary chunk fails, the database server brings the mirror chunk online automatically. For more information, see Mirroring.