The 3-2-1-0 Rule to High Availability

Reliable backup is one of the foundations of availability.  When things go wrong, data can be lost.  The more data that is lost, the greater the potential business impact. Part of getting back up and running quickly is being able to restore operations to where they were before the problem started.  Sometimes, however, problems are not limited to a single occurrence.  Compounding of problems can put your backups at risk as well.  Companies who have learned this lesson the hard way commonly employ the 3-2-1-0 rule:

3: Maintain at least three copies of your data and applications. That’s the one copy you’re using and two backups.  This way, if one of your backups is unavailable for any reason (such as the backup is collocated with your primary copy and both go down), you can still recover what you need.

2: Store your backups on at least two different types of media. One reason for this is that each type of media has its own vulnerabilities, and you don’t want both of your backups susceptible to the same problem.  For example, two drives in a data center could be corrupted by the same virus or infrastructure failure.  By utilizing different media, you can reduce your exposure to the same incident preventing access to both of your backups.

1: Keep one of the backups in a different location. Consider a crisis in your primary data center, such as a fire or power failure.  If all of your copies are collocated, they can all be affected, taking down your organization.

0: Verify your recovery plan has zero errors. It is not uncommon for organizations to implement a reasonable recovery plan but fail to confirm that it performs as required.  Regular testing is essential to ensuring that, if you lose access to your data and applications, your organization can be back online in a minimal amount of time.

With the cloud, it has become much easier for organizations to employ the 3-2-1-0 rule.  Backup as a Service and Disaster Recovery as a Service provide a simple and cost-effective way to maintain multiple backups on different media in distinct locations.  This is also achieved without requiring extensive CAPEX investment.

Working with a cloud provider also enables you to access a range of technologies to assure high availability.  As Xander Uyleman from Cisco states in “The 3-Level Approach to Availability”, data and application backup is just one part of a comprehensive recovery plan.  Different technologies are required to protect your operations at a server level.  Your plan also needs to protect your site, requiring yet another set of technologies.  With the cloud, you have access to leading innovation, such as being able to backup virtual machines, automate recovery processes, and test your recovery plan without interrupting your day-to-day operations.

Learn more about how the cloud can help you maintain high availability for your organization with the 3-2-1-0 rule.

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Doug Hazelman (VMDoug)
Doug Hazelman (VMDoug)

Doug Hazelman is Vice President, Product Strategy, Chief Evangelist. Doug consults with customers, partners and industry analysts on key considerations for implementing virtual server infrastructures. He works with Veeam’s R&D team to enhance and develop new Veeam products to address market needs, and advises customers on best practices for managing virtual environments. Doug shares his expertise via the Veeam blog and other social media outlets. Doug has spoken about virtualization management at VMworld, the Nordic Virtualization Conference, Interop, and other events including regional VMUG meetings. He is a VMware vExpert for 2011 and has also appeared on's "Ask the Experts."

Prior to joining Veeam, Doug was an IT infrastructure consultant with Bennett Adelson. Earlier in his career he was the director of Product Management for Migration Solutions at Quest Software. Doug was with Aelita Software in various technical and product management roles for more than five years before it was acquired by Quest Software in 2004.

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