What is the Cloud?

Cloud computing, data centers, and virtualization, are now the dominant IT terms floating around. Brief definitions are below:

  • Cloud computing- using the Internet to access your software and store information. This software and data is no longer stored on your desktop but on servers housed at a central location. The information is typically accessed using your web browser. Examples of cloud computing are Gmail or Microsoft Office 365.
  • Data Centers- the cloud is a series of data centers. The data that is stored off site and the software that is accessed during cloud computing is housed inside a data center. If you want to see what a data center looks like follow this link.      Data Center Video
  • Virtualizing – turning a hardware based server and the applications running on that server into software in order to provide enhanced reliability and robust disaster recovery options. Providers of this software are VMware, Microsoft, and Citrix.

When considering switching to cloud based application the question of security and reliability should be at the forefront of every conversation.   The least expensive level of cloud computing is called a Co-Location facility or Co-Lo. No standards exist for defining a reliability level for a Co-Lo. A Co-Lo typically provides a much better environment for your servers and data than a premise based computer room at a lower cost than a certified data center.  Data centers have to meet building criteria based upon standards established by the “Uptime Institute”. Certification is ranked Tier 1 through Tier 4 and measures projected uptime.

A Tier 4 data center is the least likely to fail. Tier 4 is designed to host critical servers and computer systems. Tier 4 is designed with redundant cooling, power supply, network links, and storage and security systems.  Tier 1 is the least reliable certified data center. Below are the basics for certification:

  • Tier 1 = Non-redundant capacity (one server and uplink). Onsite generator and battery powered inverter providing all AC current. Guarantees 99.671% availability of data.
  • Tier 2 = Tier 1 Capacity and redundant capacity. Guarantees 99.741% availability.
  • Tier 3 = Tier 1, Tier 2 and dual-powered equipment and multiple uplinks. Guarantees 99.982% availability.
  • Tier 4 = Tier 1, Tier 2, Tier 3 and all components are fully fault-tolerant including uplinks, storage, chillers, HVAC systems, servers.  All dual-powered. Guarantees 99.995% availability.

The small difference in guaranteed availability seems insignificant until you consider how much down time is included in the 99.xxx availability. In theory, Tier 4 is only unavailable less than 30 minutes a year and Tier 2 could be unavailable as much as 24 hours in a year. Tier 1 is potentially unavailable about 29 hours per year.

I hope this brief article helps explain cloud computing, data centers, and virtualization. If you have additional questions feel free to call or email me.

Craig Hodges



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