DBAM Storage Model and Terminology

The DBAM storage Model is described in [2]. This model supports two device types, the Directory Data Device and the Transaction Device

  1. The Directory data device stores different types of data. It can be one or maximal 6 different raw devices. It is important to understand which data are stored in the different parts of the data device and how these data subsets are called in the configuration tools

    1. Real directory object data (called REAL): complete set of Information about one directory entry. These data subset is stored in blocks of fixed size.

    2. Pseudo object data (called PSEUDO): references to REAL used by DBAM. These data subset is stored in blocks of fixed size.

    3. Attribute Value Index Data (called AVIDX): standard Indexes (see chapter 6). These data subset is stored in blocks of fixed size.

    4. Bit String Data (called BITSTR): References to subordinates. These data subset is stored in blocks of variable size.

    5. Tree data (called TREE): hierarchical relationships between entries. These data subset is stored in blocks of variable size.

    6. General data (called GENERAL): other data. These data subset is stored in blocks of variable size.

  2. The Transaction device only contains transaction logs and is always a separate raw device