System Tables That Manage Storage

Two system tables in the master database, sysusages and sysdevices, and three more in each user database (syssegments, sysindexes, and syspartitions) track the placement of databases, tables (including the transaction log table, syslogs), and indexes.

The relationship between the tables is illustrated below.

System tables that manage storage
Image shows the system tables that manage storage: sysusages and sysdevices in the master database, and syssegments, sysindexes, and syspartitions in the user databases.