An ITIL-Based Approach to Building Effective Storage Capacity Management in Support

Author: Joel Wenger

Abstract

Deploying storage typically results in over-purchasing of hardware and poor allocation of resources. This white paper illustrates how to use ITIL capacity management to help your company better buy and deploy storage.

Introduction

Understanding the current state of your storage infrastructure-what capacity you have, where it is located, who is using it, who is paying for it, how efficiently it is being used, and how well it is meeting SLAs-is fundamental to intelligently planning, provisioning, and managing storage. Buying and deploying storage as it is often done on a per-project basis- based on loose estimates of immediate and future required capacity, application requirements, and response times-typically results in over-purchasing of hardware and poor allocation of resources. These are costly mistakes, with less than desired operational efficiencies, including the risk of outages when storage is simply unavailable.

However, most organizations do not have the tools and processes in place to effectively gather and track the information necessary to make an informed decision about storage provisioning. Traditional, manual methods are highly resource- and labor-intensive, extremely inefficient and costly, and deliver only a subset of information. As a result, decisions to purchase or configure more storage are most often based on perceived instead of real needs and expectations, and estimated instead of actual consumption and performance.

The Solution: An ITIL-based Approach

Capacity management is a sub-process within the Information Technology Infrastructure Library (ITIL) framework that allows companies to quickly, easily, efficietly, and cost-effectively gather comprehensive information about storage capacity, utilization, and performance across the enterprise. Utilizing proven processes and solutions that automate the complex data gathering and analysis process, capacity management helps organizations set better service level agreements (SLAs) and more accurately understand costs for meeting SLAs; understand costs for setting up an efficient, profitable recovery mechanism; create a better financial model; ensure more efficiently run operations; and ultimately, achieve information lifecycle management by:

• Ensuring that the need for capacity is cost-justifiable
• Ensuring more efficient use of resources
• Managing supply against the demand, especially as it relates to the potential for providing new services
• Defining IT capabilities proactively to meet real needs
• Quantifying utilization to predict future requirements based on previous growth rates
• Building a business case for justifying new hardware purchases or support consolidation efforts if capacity requirements are shrinking
• Justifying IT expenditures against ROI
• Performing financial modeling based on real data

This document presents guidelines and considerations for implementing effective capacity management capabilities within your organization, using a practical, industry-proven ITIL-process-based approach for best results. (Performance management, an important sub-discipline of capacity management, will be addressed separately in a follow-on white paper.)

Storage Model Considerations

The environment in which you deploy storage can have a significant impact on how effectively you can manage its capacity and performance. As detailed in the following chart, a decentralized storage environment makes it difficult to provide adequate storage resources from the outset, and to manage those resources effectively over time. A centralized environment, on the other hand, in which a pool of storage resources is allocated to individual hosts, makes it easier to adjust for growth-even with increased complexity in balancing capacity and performance utilization.

A payback can often be realized by moving from a decentralized to a centralized environment. If capacity management has already been implemented in a decentralized environment, cost savings from a transition will be realized even more quickly.