capacity management

What is capacity management?

Capacity management is the broad term describing a variety of IT monitoring, administration and planning actions that ensure that a computing infrastructure has adequate resources to handle current data processing requirements, as well as the capacity to accommodate future loads.

The tools used for capacity management include spreadsheets with manually compiled performance information, the "element managers" often included with computing devices, and specialized software or hardware that provides extremely detailed insights into how computing components function.

Managing IT infrastructure has become more complex in recent years and companies have augmented or replaced in-house systems with resources provided by cloud services. The cloud services require the same degree of capacity management, performance management and capacity planning as on-premises gear, so more holistic capacity management and planning tools have been introduced to adequately address these hybrid environments in the management process.

Capacity management in IT

The methodologies and processes used for IT capacity management may vary, but however it is accomplished, at minimum, it requires the ability to monitor IT resources closely enough to be able to gather and measure basic performance metrics.

With that data in hand, IT managers and administrators can set baselines for operations to meet a company's processing needs. The baselines -- or benchmarks -- represent average performance over a specific period and can detect deviations from those established levels.

Capacity management vs. capacity planning

Capacity planning is typically based on the results and analysis of the data gathered during capacity management activities. By examining performance variances over time, IT management can use those statistics to help develop models describing anticipated processing, which they can use for short- and long-term planning.

By noting which particular resources are being stressed, admins can revise current configurations and IT planners can assemble purchasing plans for hardware and software that will help meet future demands.

How capacity management works

Capacity management tools measure the volumes, speeds, latencies and efficiency of the movement of data as an organization's applications process it. All facets of data's journey through the IT infrastructure must be monitored, so capacity management must be able to examine the operations of all the hardware and software in an environment and capture critical information about data flow.

Measurement and analysis tools must be able to observe the individual performances of IT assets, as well as how these assets interact. A comprehensive capacity management process should be able to monitor and measure the following IT elements:

• Servers.
• End-user devices.
• Networks and related communications devices.
• Storage systems and storage network devices.
• Cloud services.

Whether capacity management is achieved via software, hardware or manual means -- or a combination of any of those -- it relies on the interception of data movement metrics and the internal processes of individual components. Most IT hardware products ship with applications that can extract basic performance information. While the information is useful, it usually is limited and may only pertain to a few performance factors.

To get more detailed statistics, an admin would typically run a software utility program designed to address specific functionalities of a component. For example, Iometer is a free, open source utility originally developed by Intel that provides details about processing by servers, clusters of servers or individual end-user computers. One of the key metrics that Iometer provides is input/output operations per second, or IOPS, which is a basic measure of the transfer rate of data during processing.

Emulation programs are also effective tools for capacity management. These programs mimic application programs such as database management systems to determine how a system is likely to perform under similar loads in production environments. Application emulators typically include their own sets of test data to help ensure accurate and consistent results across disparate equipment.

Another approach to capacity management involves the use of hardware-based monitoring devices. Generally, these management systems focus on network performance and can provide comprehensive information on most aspects of data movement. The components of these systems vary, but a basic configuration will include control devices -- typically servers with specialized software -- and network TAPs, or network Test Access Points, devices that physically hook into particular elements of a network to capture information about data traffic as it occurs.

Components of capacity management

Capacity management could have a narrow scope, providing high-level information on a variety of infrastructure components or providing detailed metrics related to one segment of the computing environment. The trend, however, is to gather as much information as possible and then to attempt to correlate those measurements into an application-centric picture. That picture focuses on the performance and requirements of mission-critical applications across the environment, rather than how individual components are performing.

Still, to achieve that application-centric view of capacity management, virtually all elements of the IT infrastructure must be monitored. In addition, the definition of capacity must be broad enough to consider the impact an application will have on processing power, memory, storage capacity and speed for all physical and software components comprising an infrastructure.

Performance -- or throughput -- is a key metric in capacity management as it may point to processing bottlenecks that affect overall application processing performance. The central processor unit in servers and other connected devices, such as routers, storage and controllers, should be monitored to ensure that their processing capabilities are not frequently "pinning" at or near 100%. An overtaxed processor would be a candidate for upgrading.

Memory is also a factor in capacity management. Servers and other devices use their installed memory to run applications and process data -- if too little memory is installed, processing will slow down. It's relatively easy to determine if a server has adequate memory resources, but it's also important to monitor other devices in the environment to ensure that insufficient memory doesn't turn them into processing bottlenecks.

Physical space is what is most commonly associated with capacity management, with the focus generally on storage space for applications and data. Storage systems that are near capacity will have longer response times, as it takes longer to locate specific data when drives -- hard disk or solid-state -- are full or nearly full. As with processor and memory measurements, it's important to monitor space usage in devices other than servers and end-user PCs that may have installed storage used for caching data.

Capacity management in networking

Managing the capacity of IT networks can be a complex process given the number of different networking elements in an enterprise environment.

The number and type of networks being monitored is likely to vary as well. In addition to the wired and wireless Ethernet-based network infrastructure that connects servers to storage, end-user devices, networking gear, etc., comprehensive network capacity management must also consider dedicated storage networks based on Fibre Channel (FC) technologies. The FC networks are likely to be physically isolated from other data networks and will require different tools for monitoring and management.

External networking should also be monitored. Again, different tools must track traffic and performance for network connections to remote offices and users, the internet and to cloud services.

The networking devices that should be monitored include network interface cards, network switches, network routers, storage network interfaces (e.g., host bus adapters), storage network switches and optical network devices.

Although capacity management for networks doesn't directly address security, it can be a good method of keeping track of network access, which can help inform security procedures.

Benefits of capacity management

Capacity management provides many benefits to an IT organization and helps overall management of a computing infrastructure.

In addition to ensuring that systems are performing at adequate levels to achieve a company's goals, capacity management can often provide cost savings by avoiding over-provisioning of hardware and software resources. It can also help save money and time by identifying extraneous activities like backing up unused data or maintaining idle servers.

Good capacity management can also result in more-effective purchasing to accommodate future growth -- it more accurately anticipates needs and, thus, makes purchases when prices may be lower.

By constantly monitoring equipment and processing, problems that might have hindered production may be avoided, such as bottlenecks or imminent equipment failures.