07-03-13 | Blog Post

High Availability & Redundancy: Smart Design for Disaster Recovery

Blog Posts

We’ve just launched our latest white paper, Disaster Recovery! This white paper is ideal for executives and IT decision-makers seeking a primer as well as up-to-date information regarding disaster recovery best practices and specific technology recommendations, including cloud-based disaster recovery options.

Download the Disaster Recovery white paper.

Read below for an excerpt about designing for mission-critical application and data recovery:

4.2. Designing for Recovery

High Availability Infrastructure
Strategic data center design involving high availability and redundancy can help support larger companies that rely on mission-critical (high-impact) applications. High availability is a design approach that takes into account the sum of all the parts including the application, all the hardware it is running on, power infrastructure, and the networking behind the hardware.

Using high availability architecture can reduce the risks of lost revenue and customers in the event of Internet connectivity or power loss – with high availability, you can perform maintenance without downtime and the failure of a single firewall, switch, or PDU will not affect your availability. With this type of IT design, you can achieve 99.999%, meaning you have less than 5.26 minutes of downtime per year.

High availability power means the primary power circuit should be provided by the primary UPS (Uninterruptible Power Supply) and be backed up by the primary generator. A secondary circuit should be provided by the secondary UPS, which is backed up by the secondary generator. This redundant design ensures that a UPS or generator failure will never interrupt power in your environment.

For a high availability data center, you should seek not only a primary and secondary power feed, but also a primary and secondary Internet uplink if purchasing Internet from them. Additionally ensure any available hardware, firewalls or switches include redundant hardware.

If using managed services and purchasing a server from a data center, ensure all of the hardware is configured for high availability, including dual power supplies and dual NIC (network interface controller) cards. Ensure their server is also wired back to different switches, and the switches are dual homed to different access layer routing so there is no single point of failure anywhere in the environment.

Offsite backup and disaster recovery are still important; as high availability cannot help you recover from a natural disaster such as a flood or hurricane. Additionally, disaster recovery comes after high availability has completely failed and you must recover to a different geographical location.

Redundant Infrastructure
Redundancy is another factor to consider when it comes to disaster recovery data center design. With a fully redundant data center design, automatic failover can ensure server uptime in the event that one provider experiences any connectivity issues.

This includes multiple Internet Service Providers (ISPs) and fully redundant Cisco networks with automatic failover. Pooled UPS (Uninterruptible Power Supply), battery and generators can ensure a backup source of power in the event one provider fails. View an example of Online Tech’s redundant network and data centers below:

Redundant Connectivity and Network

Cold Site Disaster Recovery
A cold site is little more than an appropriately configured space in a building. Everything required to restore service to your users must be retrieved and delivered to the site before the process of recovery can begin. As you can imagine, the delay going from a cold backup site to full operation can be substantial.

Warm Site Disaster Recovery
A warm site is leasing space from a data center provider or disaster recovery provider that already has the power, cooling and network installed. It is also already stocked with hardware similar to that found in your data center, or primary site. To restore service, the last backups from an offsite storage facility are required.

Hot Site Disaster Recovery
A hot site is the most expensive yet fastest way to get your servers back online in the event of an interruption. Hardware and operating systems are kept in sync and in place at a data center provider’s facility in order to quickly restore operations. Real time synchronization between the two sites may be used to completely mirror the data environment of the original site using wide area network links and specialized software. Following a disruption to the original site, the hot site exists so that the organization can relocate with minimal losses to normal operations. Ideally, a hot site will be up and running within a matter of hours or even less.

When you partner with a data center/disaster recovery provider, you’re sharing the cost of the infrastructure, so it’s not as expensive if you were to have an entirely secondary data center.


You might be interested in our other white papers on:

HIPAA Compliant Hosting
This white paper explores the impact of HITECH and HIPAA on data centers. It includes a description of a HIPAA compliant data center IT architecture, contractual requirements, benefits and risks of data center outsourcing, and vendor selection criteria.

PCI Compliant Hosting
This white paper explores the impact of the PCI DSS standard on data centers and server infrastructure, describes the architecture of a PCI compliant data center both technically and contractually, and outlines the benefits and risks of data center outsourcing, and vendor selection criteria.

Mobile Security
This white paper explores approaches to mobile security from risk assessment (what data are truly at risk), enterprise architecture (protect the data before the devices), policies and technologies, and concludes with an example of a mobile security architecture designed and implemented within a hospital environment in which both enabling caregivers and protecting privacy, integrity, and confidentiality are paramount.

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