Call Today 1-877-740-5028

High Availability

The Anatomy of a High-Availability Rack

This paper is intended for small and medium-sized business executives in need of an IT infrastructure that provides always-on power and always-connected Internet 24 x 7 x 365.

With its redundant power and Internet connectivity, high availability racks are uniquely designed to withstand single points of failure. Each server should have two power sources and two paths to an Internet connection, highlighting just a few of the points that make high availability servers perfect for businesses that depend on their servers to be always on and always connected to the Internet.


Simply put, business today has evolved to rely on computers and the Internet. More and more frequently, businesses are turning to and relying on the Internet to generate revenue.

But what happens in the event power is lost or Internet connectivity is disabled? The short answer is that your business will lose money. And the longer your business is offline, the more difficult it becomes to rebound from the loss of revenue. This is especially true for small businesses, particularly those that rely solely on Internet sales and commerce. Using a High Availability (HA) architecture can greatly reduce the risk of your business losing profit due to a disaster or other anomaly that wipes out power or Internet. How does a High Availability server provide this type of protection? The answer lies in the anatomical design of the server rack.

The purpose of this paper is to describe the anatomy of a high availability rack. This paper will illustrate the redundant power supply and redundant Internet connectivity that ensures a greater level of protection against the loss of power or network connectivity and allowing you to properly maintain your equipment. This design keeps your company’s computers online, maximizing your potential to generate revenue.

Power Distribution

As figure 1 displays, the rack is designed to withstand any single point of power failure. The rack is supplied power through two diverse power feeds. The two power feeds from the utility company travel different paths into Online Tech data centers. In the event one feed is disrupted, there is a second feed providing the data center with power. Each power plug is fed into a different power strip. Power strips provide digital readouts, which aid in monitoring power levels, helping to avoid tripping a circuit breaker. The power strips are connected to two different PDUs (Power Distribution Units). And each PDU is connected to a pool of redundant batteries or an N+1 UPS (Uninterruptible Power Supply) pool, which cleans and distributes the power while providing an additional backup.

The clean power from the UPS is stable; therefore, any fluctuation in power, both power surge and brown out, is regulated by the UPS. So, equipment in Online Tech data centers receive a constant, stable level of power. The entire power feed is wed to two generators.

Generators at Online Tech facilities are either diesel or natural gas. If power is lost, the batteries send a signal to the generators, which will switch on and activate thereafter. This design inherently creates redundancy. In other words, if one point of power distribution should fail, there is a backup. There is no single point of power failure.

Figure 1


Network Distribution

Designed to replicate the same redundancy as the power distribution, the network and Internet connectivity offer no single source of failure. Two core routers are fed from
multiple ISPs (Internet Service Provider). Each ISP feed is cross-meshed between both routers and OT’s network access switches, providing two diverse network paths. The feed is then sent through two universal threat management devices (UTMs), which provide redundant protection to potential threats. The universal threat management devices provide firewall protection, VPN, denial of service, intrusion detection, port scan and load balancing. From the universal threat management devices, the network connection is sent to two rack network switches, which disperse the network connectivity to all servers contained within the rack.

Increased Redundancy and Availability Beyond a Single Data Center
In addition to the high availability design at Online Tech data centers, there are a number of customer options available, which provide increased redundancy and high availability to meet your business needs. Online Tech has data centers in separate power grids. Hosting your primary data center in Ann Arbor and your backup/disaster recovery in Flint, for example, provides increased redundancy, as each data center resides in a different power grid.

ha figure2

Preventative Maintenance and High Availability

If your business relies solely on ecommerce, you cannot afford to be down, not even for preventative maintenance. However, if preventative maintenance is not performed, the risk for a failure increases.

Inevitably, preventative maintenance must be done to your equipment. Therefore, the high availability package at Online Tech is designed to allow you to conduct the necessary preventative maintenance on your equipment, while still maintaining customer access to your site.

With two servers, properly configured, one server can be shut down for preventative maintenance, while customer traffic is maintained by the other server. For example, if you have two network switches in the rack and all your servers are connected to it, you can unplug one server, do preventative maintenance on it, plug it back in then do the same with the other switch. All the time, the servers never go down. That’s high availability.


At Online Tech, we offer a high availability solution that guarantees your company’s computing environment is available.

In addition, we offer backup and disaster recovery (DR) options with our HA package. A replicated server is available at an offsite data center such as our Flint Township data center, which resides in a different power grid than our Ann Arbor data centers, providing even more redundancy.

The anatomy of the rack is designed to provide businesses, like yours, that rely on the Internet and their network to drive their business. These businesses cannot afford to be offline. Therefore, a High Availability package with Online Tech provides the peace-of-mind to know your business will be always on and always connected to the Internet.

About Online Tech

Online Tech is the leader in secure, compliant hosting services including private cloud hosting, managed cloud hosting, hybrid cloud hosting, managed dedicated servers, disaster recovery, offsite backup services, andMichigan colocation. Online Tech’s Midwest data centers assure mission critical applications are always available, comply with government & industry regulations, and continue operating after a disaster. Backed by independent HIPAA, PCI, SAS 70, SSAE 16 Type, SOC 2, and SOC 3 audits, Online Tech delivers the security, privacy, and availability expected from world class data center operators. For more information, call (877) 740-5028 or email This email address is being protected from spambots. You need JavaScript enabled to view it. .

Download the PDF


A Company We Can Rely On

We had to find a company that we could rely on. For the last seven years, Online Tech has been able to provide reliability. DataMail was able to leverage everything that they had for a reasonable cost. We could never ever do this on our own.

- William Hayden, President & CEO, DataMail

Have Questions?
Call Today 1-734-213-2020


Live Chat
Events 2