Seven tiers of disaster recovery
Encyclopedia
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.
Although the original known published concept dates back to the 1990’s, 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. 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).
The seven tiers of business continuity solutions offer a simple method to define current service levels and associated risks.
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.
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 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.
Disaster recovery
Disaster recovery is the process, policies and procedures related to preparing for recovery or continuation of technology infrastructure critical to an organization after a natural or human-induced disaster. Disaster recovery is a subset of business continuity...
was originally defined by Share
SHARE (computing)
SHARE Inc. is a volunteer-run user group for IBM mainframe computers that was founded in 1955 by Los Angeles-area IBM 701 users. It evolved into a forum for exchanging technical information about programming languages, operating systems, database systems, and user experiences for enterprise users...
to help identify the various methods of recovering mission-critical computer systems as required to support business continuity.
Although the original known published concept dates back to the 1990’s, Business Continuity Planning
Business continuity planning
Business continuity planning “identifies [an] organization's exposure to internal and external threats and synthesizes hard and soft assets to provide effective prevention and recovery for the organization, whilst maintaining competitive advantage and value system integrity”. It is also called...
(BCP) and Disaster Recovery Specialists today continue to use the 7-Tiers to illustrate continuity capabilities and costs at a very high level. 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
Recovery Time Objective
The recovery time objective is the duration of time and a service level within which a business process must be restored after a disaster in order to avoid unacceptable consequences associated with a break in business continuity....
(RTO) and Recovery Point Objective
Recovery point objective
-Recovery point objective :When computers used for normal "production" business services are affected by a "Major Incident" that cannot be fixed quickly, then the Information Technology Service Continuity Plan is performed, by the ITSC recovery team...
(RPO).
The seven tiers of business continuity solutions offer a simple method to define current service levels and associated risks.
Tier 0: No off-site data – Possibly no recovery
Businesses with a Tier 0 business continuity solution have no business continuity plan. There is no saved information, no documentation, no backupBackup
In information technology, a backup or the process of backing up is making copies of data which may be used to restore the original after a data loss event. The verb form is back up in two words, whereas the noun is backup....
hardware
Hardware
Hardware is a general term for equipment such as keys, locks, hinges, latches, handles, wire, chains, plumbing supplies, tools, utensils, cutlery and machine parts. Household hardware is typically sold in hardware stores....
, 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
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
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
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
Virtual Tape Library
A virtual tape library is a data storage virtualization technology used typically for backup and recovery purposes. A VTL presents a storage component as tape libraries or tape drives for use with existing backup software.Virtualizing the disk storage as tape allows integration of VTLs with...
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
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
Tier 5 solutions are used by businesses with a requirement for consistency of data between the production and recovery data 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
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
Disk mirroring
In data storage, disk mirroring or RAID1 is the replication of logical disk volumes onto separate physical hard disks in real time to ensure continuous availability...
. There are various synchronous and asynchronous solutions available from the mainframe
Mainframe computer
Mainframes are powerful computers used primarily by corporate and governmental organizations for critical applications, bulk data processing such as census, industry and consumer statistics, enterprise resource planning, and financial transaction processing.The term originally referred to the...
storage vendors. Each solution is somewhat different, offering different capabilities and providing different Recovery Point
Recovery point objective
-Recovery point objective :When computers used for normal "production" business services are affected by a "Major Incident" that cannot be fixed quickly, then the Information Technology Service Continuity Plan is performed, by the ITSC recovery team...
and Recovery Time
Recovery Time Objective
The recovery time objective is the duration of time and a service level within which a business process must be restored after a disaster in order to avoid unacceptable consequences associated with a break in business continuity....
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.