Choosing Your Data Center

Choosing Your Data Center: What to Expect from Your Hosting Provider :PART III

By: Paul Froutan VP of Data Center Operations ,from ; developersnetwork.com

SERVICE LEVEL AGREEMENTS

Providers use Service Level Agreements (SLAs) to guarantee network uptime. These range anywhere from 99% uptime (7.2 hours of downtime per month) to 99.999% uptime (26 seconds of downtime per month). Clearly, anything less than 99.99% uptime is impractical for most applications in today’s market. However, more important than the guarantee is the payback. The payback is how much the provider will credit the customer in case of downtime. Some providers' paybacks are so low that the guarantee becomes meaningless. Others engage in what I consider to be a deceitful practice where, while they guarantee a certain uptime, they do not start paying back until the network has been down for much longer than the guaranteed time. For example, they will guarantee 99.999% uptime, which is less than 26 seconds of downtime per month. However, when you look at the payback schedule, they do not start crediting the customer until the network has been down for 30 minutes. While that technique is easy to identify, others use more subtle methods. Therefore, when scrutinizing an SLA, customers need to pay close attention to the payback schedule.

DATA CENTER SECURITY

The final and very critical component of a data center is security. There are significant differences in security needs between a colocation data center and a managed hosting data center. Hundreds, even thousands of customers pass through a colocation data center every day. It is therefore critical to maintain strict control and monitoring of the people that have access to the data center. Even in the most secure data centers, customers can damage other customers' equipment. However, in a secure managed hosting data center, only key employees have access to the data center, as customers do not access the equipment. How many people have access to the data center? Usually, it is not necessary to have more than 20 to30 people that can have unescorted access in a 10,000 square foot data center. That is a question that customers should ask their hosting provider. Most reputable providers will use a biometric system to control access to key areas. The advantage of these systems is that the activity is logged and any employees who are no longer eligible to enter the data center can be immediately removed. Also, there is no danger of lost keys or passcards.

Despite the importance of physical security, keep in mind that it is significantly easier to compromise a server through the network than by trying to gain physical access to the server. Therefore, it is critical for the hosting provider to maintain an up-to-date image of the OS that is installed on the server. It is usually not practical for a hosting provider to update the OS proactively once the server is in production as the update may cause problems with applications that the customer has loaded. However, the image deployed when a server is initially loaded with the OS should have the latest patches applied. Note that as patches are released daily, providers should have experts available to keep the image updated.

Although this article lists a few data center guidelines to help select a hosting provider that has appropriate data centers to host its servers, it is not replacement for a professional of proper education and experience. I would advise customers to consult colleagues who have had previous experience assessing data centers. Also, the best guideline in selecting a provider, just as selecting any other company, is reputation. A company that consistently has reliable facilities and treats their customers with respect will have a good reputation in the industry and the opinion of the customers is the ultimate test of a good company.

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