Disaster recovery is a plan and process to help organizations resume critical applications and resources after a disaster. Since modern businesses depend on digital resources, the impact of data loss and/or service disruptions from any disaster including but not limited to cyberattacks, hardware or software failure, and human errors can become disastrous; and so disaster recovery plans.
According to IBM, a disaster recovery plan is “a formal document created by an organization that contains detailed instructions on how to respond to unplanned incidents such as natural disasters, power outages, cyber attacks and any other disruptive events. The plan contains strategies on minimizing the effects of a disaster, so an organization will continue to operate – or quickly resume key operations.” The reason being service disruptions can lead to revenue loss, bad reputation, and disappointed customers. And the longer the disruption is there, the greater the bad impact — calling for robust disaster recovery plans.
A robust disaster recovery plan requires parameters that will help to optimize resources to quickly recover all business-critical resources. The two important objectives that play a major role in strategizing a disaster recovery plan are Recovery Point Objective (RPO) and Recovery Time Objective (RTO). Data recovery plans can be designed for enterprises based on the amount of possible loss of data and the ideal time needed to restore services to ensure the ideal results. Of course, there is a tradeoff between cost, efficiency, and speed of recovering the services, which must be calculated while creating a plan.
The most important element in making this tradeoff and creating a disaster recovery plan is distance, i.e., the distance of the disaster recovery site. In the 1980s, the Share Technical Steering Committee along with IBM designed a list of disaster recovery service levels called tiers. This count of disaster recovery tiers was originally seven, but another tier was later added to meet the modern businesses’ demands. One must understand these tiers of disaster recovery to create an effective disaster recovery plan. Let’s get to know them all.
Tier 0: No Off-site Data Backup
No saved data, backup, or information is available to be recovered because of the absence of BCP (Business Continuity Plan). No off-site data can be retrieved or recovered, and hence, it relies on local recovery only. This tier does not provide any protection in the event of a disaster. It is the same as no recovery plan.
Tier 1: Data Backup with a Cold Site
In this basic level of disaster recovery setup, data is backed up to a tape or storage vault at specific time intervals and transported to off-site facility storage (generally known as ‘cold site’). In the case of a disaster, this tier does not fulfill the need for online systems to be continuously available. Also, data can be restored only till the point of the last backup. Although this tier is a low-cost solution, the process is difficult to manage and bad at restoring all data.
Tier 2: Data Backup with a Hot Site
Data is likely to be backed up more frequently in this tier than in tier 1 and stored in a backup computer system or infrastructure (commonly known as ‘hot site’) using the required hardware at a remote location. Data retrieval becomes easier and faster since copies of critical data are stored separately from the system, eliminating the time required to obtain and manage hardware at a hot site.
Tier 3: Electronic Vaulting
Tier 3 is similar to tier 2 with some added provisions for transmission of data electronically to the hot site. Since no retrieval from an off-site is required, recovery is faster and data loss is reduced. This method saves time and effort to ship backups manually as was the case in tier 1 and tier 2. And so, electronic transmission promotes recovery in hours, thanks to bulk data transfer.
Tier 4: Point-in-Time Copies
Unlike above-mentioned tiers, in tier 4, disk-based solutions are used to create and store backups with increased frequency. Data loss is minimized due to point-in-time (PiT) copies of data, known as an active secondary site, which acts as a faster storage medium with better access time. This tier may cause data synchronization issues, affecting the management of backup data.
Tier 5: Transaction Integrity
Tier 5 is an application-based solution to maintain the transaction integrity between retail and service organizations. The primary site and remote site data are continuously backed out as a single unit to ensure minimal to no data loss. Although the cost of maintaining and running two sites is high, tier 5 ensures data loss and data recovery time is minimal with only inflight data loss.
Tier 6: Near-Zero Data Loss
With minimal to zero data loss, tier 6 is the second-best yet the efficient level of data recovery. This level uses disk mirroring or disk replication for continuous data availability. Instantaneous recovery with no data loss is the major feature of tier 6. Moreover, emergency restart at the remote site is also possible.
Tier 7: Automated Business-Integrated Solutions
The top-most tier, added later to include automation to eliminate constraints of manual processes, is the highest tier in a data recovery plan. The no-time restoration and activation of backup hot sites like tier 6 are integrated with automation. Tier 7 is the most expensive but most reliable data recovery plan needed to protect an organization’s assets with minimal manual efforts.
If carefully created and implemented, disaster recovery plans can come to aid and save a business from any hazard, thus ensuring smooth operation of the organization. It can help ensure minor to no data loss in any potential disaster and efficient restoration of all data and other digital assets of a business.