Performance Tuning for Content Manager

Chapter 5. Designing and configuring for performance 129

5.6.3 System-managed storage

Device Managers, Storage Classes, Storage Systems, Storage Groups, Migration

Policies, and Workstation Collections are the components used to build the

storage management policies that are applied to each item or part stored in a

Content Manager system. For convenience, we deal with the entire process as a

group.

Much of the design and terminology of system-managed storage (SMS) goes

back a very long time, at least in computing terms. The principle behind SMS is

that storage is assumed to be both more expensive and faster, the closer it is to

the CPU. The purpose of the system-managed storage components is to give

you the flexibility to configure the system to keep active data on faster media and

move inactive data to slower, cheaper media.

The system’s ability to achieve this depends very much on the designer’s ability

to predict the way in which data will be accessed. In general, time is a very good

indicator of the way in which files will be accessed. For forms-processing

systems, the very nature of the application is that there is a certain target time for

handling these forms, and almost every form will be actively used during that

period. At completion of the forms process, the document is rarely accessed.

For document-management systems, the period of high activity is less well

defined but typically occurs at the early part of the document life cycle. During

creation and editing, there are frequent accesses by the author or the editor as

the document is prepared for release. Most documents have high read activity

soon after release, then the read activity dies down.

Rich media and Web application information typically have a similar pattern: lots

of activity during preparation, and high read access tapering off over time. In this

environment, there can also be archiving activity to remove items from the pubic

access area when they become outdated.

Archive systems usually do not have this early life period of activity. This activity

has already occurred in the archiving application.

Time-based migration

In setting the SMS configuration, you need to match the access patterns with the

speed of the storage media. Keep the items that are likely to be accessed on fast

media and move the inactive data to slower or near-line media.

Wherever possible, spread the data on your disk based on storage classes over

multiple volumes and use the maximum number of subdirectories to reduce the

number of files per directory.