System and Storage Redundancy
One of the greatest benefits of cloud-based computing is that it does not matter where the physical computing resources and data-storage devices are located. As a result, companies often employ duplicate off-site servers or disk-storage devices through a process known as colocation. As shown in FIGURE 4-10, by employing duplicate resources, systems can failover from one location to another or can use the duplicate systems for load balancing.
FIGURE 4-10 Companies use colocated computing resources for system failover or load balancing.
In this way, the collocated resources
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make the company less susceptible to fire, acts of God, and terrorism;
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improve performance through a distributed workload; and
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make the company less susceptible to downtime due to power loss from a blackout or brownout.
Over the past few years, the low-cost options offered by IaaS providers have made hardware redundancy a must-have option for companies who rely on the availability of key applications and data. Likewise, by leveraging cloud-based storage attached network devices and cloud-based database systems, companies can also easily replicate their data, as shown in FIGURE 4-11.
FIGURE 4-11 Using cloud-based network-attached storage (NAS) devices and cloud-based databases, companies can replicate key data within the cloud.
IaaS providers allow companies to add servers, processors, and RAM to their applications on demand. IaaS providers typically provide an administrator window that allows an application administrator to select the resources the application needs—scaling resources up or down. Further, IaaS providers can also scale resource allocation up or down automatically. Customers, in turn, pay only for those resources they require.