110 IBM Content Manager OnDemand Guide
In an OAM environment, object storage groups allow the storage administrator to define an 
object storage hierarchy. The object storage hierarchy classifies storage areas according to 
location and, therefore, according to retrieval response time. Each object storage hierarchy 
must contain an object directory, containing control information about each object. 
Additionally, the hierarchy can have the following items:
/SM590000DB2 object storage tables on a hard disk drive
/SM590000Optical volumes that are associated with optical libraries (real or pseudo), and stand-alone 
or operator-accessible optical disk drives
/SM590000Tape volumes that are associated with tape libraries or stand-alone tape drives
SMS management class
Management classes define the space and availability requirements for datasets. Class 
attributes control backup, migration, retention of data, and release of unused space. OSMC 
uses information from the management classes to determine the automatic management 
processes that need to be performed on corresponding OAM objects.
Automated Class Selection routine
Automated Class Selection (ACS) routines are used to assign class and storage group 
definitions to datasets and objects. ACS routines are written in the ACS language, which is a 
high-level programming language that is similar to the language that is used for the 
construction of TSO CLISTs. The ACS translator is used to convert the routines to object form 
so that they can be stored in the SMS configuration.
OAM collection
A collection is a group of objects that typically have similar performance, availability, backup, 
retention, and class transition characteristics. A collection is used to catalog many objects, 
which, if cataloged separately, can require a large catalog. Every object must be assigned to 
a collection. Object names within a collection must be unique; however, the same object 
name can be used in multiple collections. Each collection belongs to only one object storage 
group. Each storage group can contain from one to many collections.
5.3.2  OAM configuration recommendations
This section provides a list of recommendations for you to review and consider when you 
configure OAM for Content Manager OnDemand. They are classified in the following 
categories:
/SM590000General
/SM590000DB2
/SM590000Devices
/SM590000Tapes
/SM590000Maximum Object Size (MOS)
/SM590000Optical platters
/SM590000ARS.CFG setting
Important: A collection is the only interface that is used by the administrator to determine 
how to store objects in OAM. It is used when you create a storage set.