A chunk is a unit of disk space used to store database data that IDS manages. For CMS, each dbspace contains one chunk. The size of each chunk depends on the data requirement specification of CMS. The following figure shows an example of chunk sizing. IDS requires the rootdbs, physdb, and logdbs dbspaces, but these databases store minimal data. Dbspace dbtemp is larger and is used for temporary data space. Dbspace cmsdbs is the location that stores all CMS data and it contains the largest chunk of data.