High Availability And Disaster Recovery Concepts Design Implementation Pdf
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- High Availability and Disaster Recovery overview
- SAP HANA high-availability planning guide
- High Availability and Disaster Recovery
High Availability and Disaster Recovery overview
High availability is a quality of computing infrastructure that is important for mission-critical systems. High availability permits the computing infrastructure to continue functioning, even when certain components fail. High availability is a quality of computing infrastructure that allows it to continue functioning, even when some of its components fail.
This is important for mission-critical systems that cannot tolerate interruption in service, and any downtime can cause damage or result in financial loss.
Highly available systems guarantee a certain percentage of uptime—for example, a system that has The basic elements of high availability The following three elements are essential to a highly available system:.
Technical components enabling high availability The following systems are commonly used in highly available systems, and help implement the concepts of redundancy, monitoring and failover:. Microsoft Azure provides a variety of tools and mechanisms that can help you achieve reliability. These include published SLAs for Azure services, replication and disaster recovery mechanisms such as Azure Backup and Azure Site Recovery , health probes and check functions to obtain data about the status of operational systems, and more.
Below is a quick checklist that can help you get your requirements and architecture in place while using the relevant Azure capabilities to support your high availability strategy.
Consult Azure documentation to see the guaranteed SLA for the services you are using. If you require a higher SLA than that guaranteed by Azure, you can set up redundant components with failover.
Start with a Failure Mode Analysis FMA Identify the types of failure you might experience, the implication of each type of failure, and recovery strategies. Based on your FMA, identify the level of redundancy required for each component. Avoid single points of failure and use load balancing to distribute requests between redundant components.
Consider costs Remember that each redundant layer effectively doubles your cloud costs at least for the period the redundant component is active.
Ensure you have licenses and infrastructure to support the additional, redundant instances, including storage, networking and bandwidth.
Consider resiliency Ensure that systems can fail gracefully and restore operations without disruption of service. Isolate critical resources, use compensating transactions and use asynchronous operations to ensure that if a component fails, business operations can continue and be applied to a redundant component.
It is not possible to failover or recover if you did not replicate fresh data to the redundant component prior to failure. Instructions should be short and clear enough to use in case of emergency. To ensure reliability you should test the system under realistic failure conditions. Use fault injection testing see an example to test different failure scenarios, including a combination of failures, and measure recovery time. Test both failover and failback.
Any change can result in failure When you provision Azure VMs or other services, deploy new application code and apply configuration changes, the changes introduced could result in failure.
Having an automated, consistent deployment process can minimize the chance of errors and failures, and help you recover more easily. Consider availability in your release process Design your release process to enable updates with minimum disruption of service—try to achieve rolling updates that do not require downtime of critical components.
You can use blue-green releases or similar strategies to have several versions of your production environment available simultaneously and switch between them to move to a new version.
Plan for rollback Design a rollback process that can help you automatically restore systems to a previous working version. Detecting failures in time is critical to high availability. Implement Azure health probes and use check functions to get fresh data about service availability. You should always aim to run check functions from outside an application. Degrading health metrics can provide a warning signal that failure is about to happen.
Create an early warning system by identifying key indicators of application health and alerting operators when a system reaches a problematic threshold value. Watch subscription limits If you go over the allowed limits of one of your Azure services, you may experience failures. Ensure you are aware of the storage, compute, throughput and other limitations of each Azure service you use, monitor for the limited metrics and act before you go into overage.
Azure availability zones Azure Availability Zones allow you to deploy applications across multiple data centers; protecting applications against outages in any one Azure data center. Azure offers several options for high availability, from availability sets that operate locally within an AZ, to region pairs which run applications across different geographical regions. Proximity placement groups allow users to decide where the compute resources they deploy in Azure are placed within an Azure region, making it possible to locate them all within the same data center and therefore cutting down the associated network latencies.
This post goes in detail about how Azure proximity placement groups work and the advantages they provide when combined with Cloud Volumes ONTAP high availability deployments in Azure. Cloud Central. View All Blogs. Read Next:. More about Azure High Availability. Jan 20, AM. The basic elements of high availability The following three elements are essential to a highly available system: Redundancy —ensuring that any elements critical to system operations have an additional, redundant component that can take over in case of failure.
Monitoring —collecting data from a running system and detecting when a component fails or stops responding. Failover —a mechanism that can switch automatically from the currently active component to a redundant component, if monitoring shows a failure of the active component.
Technical components enabling high availability The following systems are commonly used in highly available systems, and help implement the concepts of redundancy, monitoring and failover: Data backup and recovery —a system that automatically backs up data to a secondary location, and recovers back to the source. This can be used to set up redundancy and failover.
Learn more in our in-depth guide to Azure backup options. Load balancing —a load balancer manages traffic, routing it between more than one system that can serve that traffic. The load balancer can be aware that one of the target systems has failed, and redirect traffic to another available system, thus implementing monitoring and failover.
Clustering —a cluster contains several nodes that serve a similar purpose, and users typically access and view the entire cluster as one unit. Each node in the cluster can potentially failover to another node if failure occurs. By setting up replication within the cluster, you can create redundancy between cluster nodes. A 5-Step Azure High Availability Checklist Microsoft Azure provides a variety of tools and mechanisms that can help you achieve reliability.
Define Availability Requirements Identify the cloud workloads that require high availability and their usage patterns. Perform End-to-End Testing To ensure reliability you should test the system under realistic failure conditions. Additional tests you can conduct to increase your level of confidence: Identify failures under load —perform realistic load testing until a system fails, and observe how failure mechanisms behave.
Run disaster recovery exercises —conduct a planned or unplanned experiment where systems go down and your team must quickly operate according to your disaster recovery plan. Test health probes —the Azure load balancer uses health probes to identify component failure. Test your probes to ensure they respond correctly in case of failure. Test monitoring systems —periodically check that data from monitoring systems is accurate, to ensure you can detect failure in time.
Deploy Applications Consistently Any change can result in failure When you provision Azure VMs or other services, deploy new application code and apply configuration changes, the changes introduced could result in failure. Use probes and check functions to detect failure in time 5. Monitor Application Health Detecting failures in time is critical to high availability. Learn more about Azure High Availability Azure availability zones Azure Availability Zones allow you to deploy applications across multiple data centers; protecting applications against outages in any one Azure data center.
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SAP HANA high-availability planning guide
High Availability HA provides a failover solution in the event a Enterprise Control Room service, server, or database fails. Disaster Recovery DR provides a recovery solution across a geographically separated distance in the event of a disaster that causes an entire data center to fail. We do not provide an internal HA or DR solution. Rather the Automation Anywhere components and configuration leverage your existing HA and DR infrastructure, load balancing, and failover systems to protect your bots and related data. See your data center administrator for your approved local HA and DR procedures. Enterprise Control Room is flexible enough to process a large number of requests. Deploy multiple instances of either Enterprise Control Room or Enterprise client on multiple physical or virtual servers, as needed.
It seems that you're in Germany. We have a dedicated site for Germany. Companies and other organizations depend more than ever on the availability of their Information Technology, and most mission critical business processes are IT-based processes. Business continuity is the ability to do business under any circumstances and is an essential requirement modern companies are facing. High availability and disaster recovery are contributions of the IT to fulfill this requirement. And companies will be confronted with such demands to an even greater extent in the future, since their credit ratings will be lower without such precautions. Redundancy can and should be implemented on different abstraction levels: from the hardware, the operating system and middleware components up to the backup computing center in case of a disaster.
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High Availability and Disaster Recovery
High availability is a quality of computing infrastructure that is important for mission-critical systems. High availability permits the computing infrastructure to continue functioning, even when certain components fail. High availability is a quality of computing infrastructure that allows it to continue functioning, even when some of its components fail. This is important for mission-critical systems that cannot tolerate interruption in service, and any downtime can cause damage or result in financial loss.
Disaster recovery is possible when you have two identical JSA systems in separate geographic environments that are a mirror of each other, and data is collected at both sites. Enable disaster recovery DR when you forward live data, for example, flows and events from a primary JSA system, to a parallel system at another site. Forwarding data uses off-site forwarding , which is set up on both the primary and secondary deployments. You can set up disaster recovery with deployments that are in different geographical locations. Primary JSA console and backup console --A hardware failure solution, where the backup console is a copy of the primary server, with the same configuration.
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This guide assumes that you already have an understanding of the concepts and practices that are generally required to implement an SAP HANA high-availability system. Therefore, the guide focuses primarily on what you need to know to implement such a system on Google Cloud. The following tables describe SAP and Google Cloud features that are used to provide high availability. Compute Engine monitors the state of the underlying infrastructure and automatically migrates your instance away from an infrastructure maintenance event. No user intervention is required.
What's new in Storage-based high availability and disaster recovery for PowerHA SystemMirror Enterprise Edition for AIX Read about new or significantly changed information for the storage-based high availability disaster r ecovery topic collection. How to see what's new or changed In this PDF file, you might see r evision bars in the left mar gin that identify new and changed information. Disaster recovery in QRadar deployments Primary QRadar Console and backup QRadar Console Configuring the IP address on the backup console Backup and recovery Event and flow forwarding from a primary data center to another data center Event and flow forwarding configuration Load balancing of events and flows between two sites Restoring. High availability disaster recovery HADR provides a high availability solution for both partial and complete site failures. HADR protects against data loss by replicating data changes from a source database, called the primary database, to the target databases, called the standby databases.
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