A Comprehensive Analysis of Disaster Recovery Tiers

The article discusses the seven tiers of disaster recovery, which are categorized based on the methods used to recover mission-critical computer systems and support business continuity. The tiers range from Tier 0 (no off-site data) to Tier 7 (highly automated, business-integrated solution). Each tier is described in detail, highlighting the key features and benefits of each approach.

TASK 4
The disasters are inevitable in nature due to their unpredictability and their variations. Therefore,
the best practices for the organisations is to have a disaster recovery plan in order to return to the
normal states as soon as possible. Any abruption or disruption of the business operations
resulting in the loss of revenue is termed as the disaster in the organisation. In order to minimise
the losses due to disaster, it is imperative to have a recovery plan by the organisation and their
business subsystems (Phillips, B. D., 2015). There is various ways and method for recovering the
data or the company from the disaster. These steps and measures are highly critical for the
company especially in the case of disaster. Some of the methods which can assist the company in
recovering from the disasters are mentioned below:
1. Backup systems: The Disaster Recovery (DR) has various components, and the basic
one deals with moving of data from the primary to the secondary data centre. This
process was called backing up of the data to shipping tapes offsite. A replication software
is used on the host, disk backup appliance, array along with the disk backup appliance for
copying data in an intelligent manner to the secondary site using the WAN. Replication
has been used by many data centres, but it is managed separately due to the absence of
integration of the backup software. In the current global world, the DR has been
integrated directly into the process of backup of the data. Disaster recovery has emerged
out as a feature with the backup product instead of being a different and unique product
which requires separate management. The process of virtualization has helped a great
deal in lowering the cost of hardware in the DR site (Nicolini, M. J., Wildes, R. A.,
Slawsky, J. E., Sabjan, C. A., Alexander, J. W., Freiheit, K., & Gregory, R. D. I., 2015).

One of the best practices among the backup method is the choice of “virtual cloud”. The data is
stored on the virtual choice in the offsite where the BDR features are provided which were not
available to the various organisation when they used traditional disk arrays. The transfer of data
is made faster with high speed with the development of the cloud backup. The process is better
than the disk arrays and has proved out to be more useful than other available technologies. The
process of cloud backup has allowed an automated recovery along with verification. In the case
of high demand, the use of VMs (virtual machines) is operated on demand. These VMs or virtual
machines can easily act as storage and also integrate with other backup options like hard disk
arrays while using the network attached storage (NAS) and also have the ability to operate
wholly on their remote server. Their virtual servers are also beneficial in offering superior
response times when compared to the traditional disk-based solutions when the assets and data
are retrieved. These VMs are also termed as cloud servers and are available in multiple OS
configurations and scaled in real-time dynamically.
The cloud backup is seen to come in two forms. The primary form is the one with the local
backup appliance which can easily replicate the data using the software to the cloud. The whole
process is seen to allow users in the retaining of their local backup of the data with faster
restoring while the older data is sent to the cloud. There are also direct-to-cloud backups which
are seen to allow various systems to send the data simultaneously to the cloud. However, this
process requires installing an agent in the individual system (Xiao, Z., Song, W., & Chen, Q.,
2013). Further, the on-site copy is not retained for faster restores. In either of the cases, it is seen
that the whole process is fulfilling the basic necessity of the DR where the data is secured in the
secondary site.
2. Whole system replacement:

The whole system replacements are termed as the method of recovering or replacement of the
whole processing system of the organisation. Whole system replacements in the organisation are
highly expensive. All the organisation avoid adopting to this solution in order to avoid the costs
and commercial burden. Further, the organisations are also exposed to have an ineffective plan
on the basis of the possibility of the disaster occurring (Chang, V., 2015).
However, the cases where the network is badly damaged, there is a need to replace the whole
system as soon as the data is not lost. Most of the organisations are seen to have a contract with a
company called Darksite. The company is responsible for replacing the whole network in case
the installed network is seen to fail. This process is seen to have performed every single trick and
process to save the data, but the organisation feels the need to start again from scratch. This
option is usually considered to be the last resort when all the functions and operations have
failed.
3. Tiers of disaster recovery
The seven tiers of disaster recovery were defined for identifying the various methods which can
recover the mission-critical computer systems for supporting the business continuity. The Tiers
were assigned from 0 to 7.
Tier 0: No off-site data – Possibly no recovery
The organisations having a Tier 0 business continuity solutions are seen to have none of the
business continuity plans. The organisations do not have any documentation, information,
contingency plan or backup hardware. Therefore it is impossible to recover data for such
organisations.

Tier 1: Data backup with no hot site
The organisations using the Tier 1 continuity solutions are seen to back up their data and finally
send it to the off-site storage facility. The process of transporting the backups is known as the
PTAM or the “Pick-up Truck Access Method." The organisation are prepared for their data loss
from weeks priors depending on how the backups are to be created and shipped. But this tier is
seen to lack the system which is dependent on restoration of the data.
Tier 2: Data backup with a hot site
The organisations are seen to have business continuity solutions which are seen to have a regular
backup on the tape. In this process, the backup is combined with the infrastructure and the off-
site facility for restoring the systems from tapes, in the case of any disaster. However, the
process will take several hours but the recovery time can easily be predictable.
Tier 3: Electronic vaulting
This tier is entirely dependent on Tier 2, but it also has electronically vaulted critical data.
There is a loss of data after the disaster is seen to take place as the electronically vaulted data is
typically more current. In order to Electronic Remote Vaulting, there is a high-speed
communication circuit along with automated tape library with virtual tape library at the remote
site.
Tier 4: Point-in-time copies
This tier deals with the higher amount of data accuracy in a faster manner as compared to the
users in the lower tiers. Instead of relying completely on the shipping tapes, this tier incorporates
higher disk-based solutions. The data loss of several hours is seen to be possible, but PiT or

point-in-time is easier and can be copied with larger frequency as compared to electronically
vaulted tape backups.
Tier 5: Transaction integrity
The solutions in Tier 5 are seen to be used by businesses which have a consistency along the
production data centres and recovery data centres. In such solutions, there is no loss of data, but
the functionality of such solutions is dependent on their application and use.
Tier 6: Zero or near-zero data loss
The solutions of Tier 6 is seen to maintain the data currency of highest level. These are used by
the organisation which have no tolerance for data loss require the restoration of the application.
There is no dependency of the applications or their staffs for providing the consistency in data.
This process requires some form of Disk mirroring and each solution is different from the other
and has different capabilities along with providing Recovery Points and recovery time
objectives. This solution also requires some form of automated tape solutions.
Tier 7: Highly automated, business integrated solution
This particular Tier and its solutions are seen to include various important components that were
utilised in the solution of Tier 6 along with the additional integration of automation. This
solution ensures complete consistency of the data in an efficient manner as compared to the Tier
6 solutions. In this solution, there is an automatic recovery of the applications which allowed for
the system and their restoration along with the applications in a much faster and reliable manner
as compared to the manual business continuity procedures (Alhazmi, O. H., & Malaiya, Y. K.,
2013).

References
Phillips, B. D. (2015). Disaster recovery. CRC press.
Nicolini, M. J., Wildes, R. A., Slawsky, J. E., Sabjan, C. A., Alexander, J. W., Freiheit, K., ... &
Gregory, R. D. I. (2015). U.S. Patent No. 9,122,711. Washington, DC: U.S. Patent and
Trademark Office.
Xiao, Z., Song, W., & Chen, Q. (2013). Dynamic resource allocation using virtual machines for
cloud computing environment. IEEE Transactions on parallel and distributed systems, 24(6),
1107-1117.
Chang, V. (2015). Towards a Big Data system disaster recovery in a Private Cloud. Ad Hoc
Networks, 35, 65-82.
Alhazmi, O. H., & Malaiya, Y. K. (2013, January). Evaluating disaster recovery plans using the
cloud. In Reliability and Maintainability Symposium (RAMS), 2013 Proceedings-Annual (pp. 1-
6). IEEE.