digplanet beta 1: Athena
Share digplanet:


Applied sciences






















The Seven Tiers of Disaster Recovery was originally defined by SHARE to help identify the various methods of recovering mission-critical computer systems as required to support business continuity.[1] IBM also aided in the development of the model.[2]

Although the original known published concept dates back to the 1990s, Business Continuity Planning (BCP) and Disaster Recovery specialists today continue to use the 7 Tiers to illustrate continuity capabilities and costs at a very high level.[3] The definitions for the various Tiers have been updated as technology has evolved in support of today's business requirements and their associated Recovery Time Objective (RTO) and Recovery Point Objective (RPO).[4]

Tier levels[edit]

When the SHARE Technical Steering Committee, working with IBM, described the levels of service for disaster recovery in the late 1980s, it produced a model that used Tiers 0 through 6. As a result of the introduction by IBM of their Geographically Dispersed Parallel Sysplex (GDPS) system, which allowed for an organization to manage end-to-end application and data availability across multiple geographically separate sites, an additional seventh tier was added to represent the industry's highest possible level of service availability.[5] The seven tiers of business continuity solutions offer a simple method to define current service levels and associated risks.[6]

Tier 0: No off-site data – Possibly no recovery[edit]

Businesses with a Tier 0 business continuity solution have no business continuity plan. There is no saved information, no documentation, no backup hardware, and no contingency plan. The time necessary to recover in this instance is unpredictable. In fact, it may not be possible to recover at all.

Tier 1: Data backup with no hot site[edit]

Businesses that use Tier 1 continuity solutions back up their data and send these backups to an off-site storage facility. The method of transporting these backups is often referred to as "PTAM" - the "Pick-up Truck Access Method." Depending on how often backups are created and shipped, these organizations must be prepared to accept several days to weeks of data loss, but their backups are secure off-site. However, this tier lacks the systems on which to restore data.

Tier 2: Data backup with a hot site[edit]

Businesses using Tier 2 business continuity solutions make regular backups on tape. This is combined with an off-site facility and infrastructure (known as a hot site) in which to restore systems from those tapes in the event of a disaster. This solution will still result in the need to recreate several hours or even days' worth of data, but the recovery time is more predictable.

Tier 3: Electronic vaulting[edit]

Tier 3 solutions build on the components of Tier 2. Additionally, some mission critical data is electronically vaulted. This electronically vaulted data is typically more current than that which is shipped via PTAM. As a result there is less data recreation or loss after a disaster occurs. The facilities for providing Electronic Remote Vaulting consists of high-speed communication circuits, some form of channel extension equipment and either physical or a virtual tape library and an automated tape library at the remote site. IBM's Peer-to-Peer VTS and Oracle StorageTek Virtual Storage Manager (VSM) Clustering are two examples of this type implementation.

Tier 4: Point-in-time copies[edit]

Tier 4 solutions are used by businesses that require both greater data currency and faster recovery than users of lower tiers. Rather than relying largely on shipping tape, as is common on the lower tiers, Tier 4 solutions begin to incorporate more disk based solutions. Several hours of data loss is still possible, but it is easier to make such point-in-time (PiT) copies with greater frequency than tape backups even when electronically vaulted.

Tier 5: Transaction integrity[edit]

Tier 5 solutions are used by businesses with a requirement for consistency of data between the production and data recovery centers. There is little to no data loss in such solutions; however, the presence of this functionality is entirely dependent on the application in use.

Tier 6: Zero or near-zero data loss[edit]

Tier 6 business continuity solutions maintain the highest levels of data currency. They are used by businesses with little or no tolerance for data loss and who need to restore data to applications rapidly. These solutions have no dependence on the applications or applications staffs to provide data consistency. Tier 6 solutions often require some form of Disk mirroring. There are various synchronous and asynchronous solutions available from the mainframe storage vendors. Each solution is somewhat different, offering different capabilities and providing different Recovery Point and Recovery Time objectives. Often some form of automated tape solution is also required. However, this can vary somewhat depending on the amount and type of data residing on tape.

Tier 7: Highly automated, business integrated solution[edit]

Tier 7 solutions include all the major components being used for a Tier 6 solution with the additional integration of automation. This allows a Tier 7 solution to ensure consistency of data above that which is granted by Tier 6 solutions. Additionally, recovery of the applications is automated, allowing for restoration of systems and applications much faster and more reliably than would be possible through manual business continuity procedures.

Other schemes[edit]

Some authorities have developed alternate DR tier schemes, also called Recovery Classes. For example, Computer Network Technologies (CNT) has developed a scheme by categorizing RTOs and RPOs into different classes.[7][8] Class 1 is the lowest level, where acceptable recovery times range from 72 hours to one week, and the most up-to-date data can be from a weekly backup. A class 4 recovery environment contains the most stringent requirements. With Class 4, the recovery time must be immediate and the data recovered must be less than one second old. The following table illustrates this Recovery Classes 4-tier scheme:

Class 1 Class 2 Class 3 Class 4
RTO 72 Hours - 1 Week 8 - 72 Hours Less than 8 Hours 0 Minutes
RPO Last full backup - Less than 1 Wk Last Backup - less than 24 Hrs Less than 15 Min. before the Event 0 Minutes


  1. ^ SteelStore Cloud Storage Gateway: Disaster Recovery Best Practices Guide. Riverbed Technology, Inc. October 2011. Retrieved 26 March 2013.
  2. ^ Disaster Recovery Levels. Robert Kern and Victor Peltz. IBM Systems Magazine. November 2003. Retrieved 26 March 2013.
  3. ^ Disaster Recovery Levels. Robert Kern and Victor Peltz. IBM Systems Magazine. November 2003. Retrieved 26 March 2013.
  4. ^ Business Continuity: The 7-tiers of Disaster Recovery. Recovery Specialties. 2007. Retrieved 26 March 2013.
  5. ^ Disaster Recovery Levels. Robert Kern and Victor Peltz. IBM Systems Magazine. November 2003. Retrieved 27 March 2013.
  6. ^ Continuous Operations: The Seven Tiers of Disaster Recovery. Mary Hall. The Storage Community (IBM). 18 July 2011. Retrieved 26 March 2013.
  7. ^ Alternate Site Recovery Techniques. CNT White Paper. 2003.
  8. ^ iSCSI-based Storage Area Networks for Disaster Recovery Operations. Matthew R. Murphy. Florida State University. College of Engineering. 2005. Page 4. Retrieved 9 May 2013.

External links[edit]

  • The tiers of Disaster Recovery and TSM. Charlotte Brooks, Matthew Bedernjak, Igor Juran, and John Merryman. In, Disaster Recovery Strategies with Tivoli Storage Management. Chapter 2. Pages 21–36. Red Books Series. IBM. Tivoli Software. 2002.

Original courtesy of Wikipedia: http://en.wikipedia.org/wiki/Seven_tiers_of_disaster_recovery — Please support Wikipedia.
This page uses Creative Commons Licensed content from Wikipedia. A portion of the proceeds from advertising on Digplanet goes to supporting Wikipedia.
1500 videos foundNext > 

Whiteboarding with Will - Tier 4 part 1 - Disaster Recovery

Disaster Recovery has long been thought of as a complex, scary, and time consuming part of system administration. In the past you had to have identical hardware in both locations as well as...

AWS Partner Webcast - Advanced Strategies for Leveraging AWS for Disaster Recovery

Amazon Web Services (AWS) provides powerful APIs and services that enable AWS to be used for production use cases, including "pay as you go" disaster recovery (DR) in the cloud. In this webinar...

Business Impact Analysis BIA High impact Strategies What You Need to Know Definitions Adoptio

https://store.theartofservice.com/business-impact-analysis-bia-high-impact-strategies-what-you-need-to-know-definitions-adoptions-impact-benefits-maturity-vendors.html Bánáthy,...

Whiteboarding with Will - Tier 4 part 2 - Disaster Recovery

Disaster Recovery has long been thought of as a complex, scary, and time consuming part of system administration. In the past you had to have identical hardware in both locations as well as...

Disaster Recovery Sites on AWS Minimal Cost, Maximum Efficiency Edit 2

Implementation of a disaster recovery (DR) site is crucial for the business continuity of any enterprise. Due to the fundamental nature of features like elasticity, scalability, and geographic...

AWS Webcast - Journey Through the AWS Cloud: Disaster Recovery

This complementary presentation discusses the use of AWS as a disaster recovery (DR) environment and how the architectural approaches to DR in the AWS cloud make a perfect learning ground for...

VMware Cloud Academy -- vCloud Air: Disaster Recovery

VMware vCloud Hybrid Service is now VMware vCloud Air. The new branding is not updated in this video, but will begin to show up in new videos in the weeks ahead The sixth in a series of seven...

PLUMgrid - Disaster Recovery - Application and Network Topology

See how PLUMgrid and Zerto can work together to create, backup, and failover a two-tiered application and it's defined network topology from one physical location to another.

vCloud Air Disaster Recovery: Pre-Requisites

The new branding is not updated in this video, but will begin to show up in new videos in the weeks ahead. This is the first of seven tutorials designed to help you get started with Disaster...

Data Protection and Disaster Recovery with Isilon SyncIQ | ID.TV

Principal Solutions Architect, Amol Choukekar, describes the basic features and functionality of Isilon SyncIQ and how it can help implement a data protection and disaster recovery strategy....

1500 videos foundNext > 

1 news items

Wed, 11 Mar 2015 09:45:23 -0700

Conçu selon le concept des Seven Tiers of Disaster Recovery, une norme qui établit les différentes méthodes de récupération de systèmes informatiques primordiaux afin de soutenir la continuité des services affaires, le centre de Dummondville est une ...

Oops, we seem to be having trouble contacting Twitter

Support Wikipedia

A portion of the proceeds from advertising on Digplanet goes to supporting Wikipedia. Please add your support for Wikipedia!

Searchlight Group

Digplanet also receives support from Searchlight Group. Visit Searchlight