Disaster Recovery
Types of disasters can include:
• Natural disasters (for example, earthquakes, floods, tornados, hurricanes, or
wildfires)
• Pandemics and epidemics
• Cyber attacks (for example, malware, DDoS, and ransomware attacks)
• Other intentional, human-caused threats such as terrorist or biochemical attacks
• Technological hazards (for example, power outages, pipeline explosions, and
transportation accidents)
• Machine and hardware failure
What is cloud disaster recovery (cloud DR)?
• Cloud disaster recovery (cloud DR) is a combination of strategies and
services intended to back up data, applications and other resources
to public cloud or dedicated service providers. When a disaster occurs,
the affected data, applications and other resources can be restored to
the local data center -- or a cloud provider -- to resume normal
operation for the enterprise.
The goal of cloud DR is virtually identical to traditional DR: to protect
valuable business resources and ensure protected resources can be
accessed and recovered to continue normal business operations.
• Importance of cloud DR
• DR is a central element of any business continuity (BC) strategy. It
improve replicating data and applications from a company's primary
infrastructure to a backup infrastructure, usually situated in a distant
geographical location.
• Before the advent of cloud connectivity and self-service technologies,
traditional DR options were limited to local DR and second-site
implementations. Local DR didn't always protect against disasters such as
fires, floods and earthquakes. A second site -- off-site DR -- provided far
better protection against physical disasters, but implementing and
maintaining a second data center imposed significant business costs.
• The following reasons highlight the importance of cloud storage and
disaster recovery:
• Cloud DR ensures business continuity in the event of natural disasters
and cyber attacks, which can disrupt business operations and result in data
loss.
• With a cloud disaster recovery strategy, critical data and applications can
be backed up to a cloud-based server. This enables quick data recovery for
businesses in the wake of an event, thus reducing downtime and
minimizing the effects of the outage.
• Cloud-based DR offers better flexibility, reduced complexities, more costeffectiveness and higher scalability compared with traditional DR methods.
Businesses receive continuous access to highly automated, highly scalable,
self-driven off-site DR services without the expense of a second data center
and without the need to select, install and maintain DR tools.
Selecting a cloud DR provider
• An organization should consider the following five factors when selecting a
cloud DR provider:
• Distance. A business must consider the cloud DR provider's physical
distance and latency. Putting DR too close increases the risk of shared
physical disaster, but putting the DR too far away increases latency and
network congestion, making it harder to access DR content. Location can
be particularly tricky when the DR content must be accessible from
numerous global business locations.
• Reliability. Consider the cloud DR provider's reliability. Even a cloud
experiences downtime, and service downtime during recovery can be
equally disastrous for the business.
• Scalability. Consider the scalability of the cloud DR offering. It must be able
to protect selected data, applications and other resources. It must also be
able to accommodate additional resources as needed and provide
adequate performance as other global customers use the services.
• Security and compliance. It's important to understand the security
requirements of the DR content and be sure the provider can offer
authentication, virtual private networks, encryption and other tools
needed to safeguard the business's valuable resources. Evaluate
compliance requirements to ensure the provider is certified to meet
compliance standards that relate to the business, such as ISO 27001,
SOC 2 and SOC 3, and Payment Card Industry Data Security Standard
(PCI DSS).
• Architecture. Consider how the DR platform must be architected.
There are three fundamental approaches to DR, including cold, warm
and hot disaster recovery. These terms loosely relate to the ease with
which a system can be recovered.
Approaches to cloud DR
• Approaches to cloud DR
• The following are the three main approaches to cloud disaster
recovery:
• Cold DR typically involves storage of data or virtual machine (VM)
images. These resources generally aren't usable without additional
work such as downloading the stored data or loading the image into a
VM. Cold DR is usually the simplest approach -- often just data
storage -- and the least expensive approach, but it takes the longest
to recover, leaving the business with the longest downtime in a
disaster.
• Warm DR is generally a standby approach where duplicate data and
applications are placed with a cloud DR provider and kept up to date
with data and applications in the primary data center. But the
duplicate resources aren't doing any processing. When disaster
strikes, the warm DR can be brought online to resume operations
from the DR provider -- often a matter of starting a VM and
redirecting IP addresses and traffic to the DR resources. Recovery can
be quite short, but still imposes some downtime for the protected
workloads.
• Hot DR is typically a live parallel deployment of data and workloads
running together in tandem. That is, both the primary data center and
the DR site use the same workload and data running in
synchronization -- both sites sharing part of the overall application
traffic. When disaster strikes one site, the remaining site continues
without disruption to handle the work. Users are ideally unaware of
the disruption. Hot DR has no downtime, but it can be the most
expensive and complicated approach.
Benefits of cloud DR
Cloud DR and backups provide several benefits when compared with
more traditional DR strategies:
• Pay-as-you-go options. Organizations that deploy do-it-yourself DR
facilities face significant capital costs while engaging
managed colocation providers for off-site DR services that often lock
organizations into long-term service agreements. A major
advantage of cloud services is the pay-as-you-go model, which
enables organizations to pay a recurring monthly charge only for the
resources and services they use. As resources are added or removed,
the payments change accordingly.
• Easy testing and fast recovery. Cloud workloads routinely operate
with VMs, making it easy to copy VM image files to in-house test
servers to validate workload availability without affecting production
workloads. In addition, businesses can select options with high
bandwidth and fast disk input/output to optimize data transfer
speeds in order to meet recovery time objective (RTO) requirements.
However, data transfers from cloud providers impose costs, so testing
should be performed with those data movement -- cloud data egress
-- costs in mind.
• Flexibility and scalability. Traditional DR approaches, usually
implemented in local or remote data centers, often impose
limitations in flexibility and scalability. The business must buy the
servers, storage, network gear and software tools needed for DR, and
then design, test and maintain the infrastructure needed to handle
DR operations -- substantially more if the DR is directed to a second
data center. This typically represents a major capital and recurring
expense for the business.
• Cloud DR options, such as public cloud services and disaster recovery
as a service (DRaaS), can deliver enormous amounts of resources on
demand, enabling businesses to engage as many resources as
necessary -- usually through a self-service portal -- and then adjust
those resources when business demands change, such as when new
workloads are added or old workloads and data are retired.
• High reliability and geo-redundancy. One essential hallmark of a
cloud provider is a global footprint, ensuring multiple data centers
support users across major global geopolitical regions. Cloud
providers use this to improve service reliability and ensure
redundancy. Businesses can readily take advantage of georedundancy to place DR resources in another region -- or even
multiple regions -- to maximize availability.
• Not bound to the physical location. With a cloud DR service,
organizations can choose to have their backup facility situated
virtually anywhere in the world, far away from the organization's
physical location. This provides added protection against the
possibility that a disaster might jeopardize all servers and pieces of
equipment located inside the physical building.
• Drawbacks of cloud DR
• The following are some drawbacks of cloud DR:
• Complexity. Setting up and maintaining cloud disaster recovery can
be challenging and require specialized expertise.
• Internet connectivity. Cloud DR needs consistent internet access,
which might be difficult in places with poor internet connectivity.
• Migration cost. Transferring large volumes of data to the cloud can be
expensive.
• Security and privacy concerns. With cloud DR, there's always the
danger of user data getting into the hands of unauthorized personnel,
since cloud providers have access to customer data. This can
sometimes be avoided by opting for zero-knowledge providers that
maintain a high level of confidentiality.
• Vendor lock-in. Once the data is migrated to a cloud-based DR
service, it can be difficult for organizations to avoid vendor lock-in or
switch to another provider.
• Dependence on third-party providers. As with any third-party
vendor, there's a risk of dependence on their service and a loss of
control over the disaster recovery process.