Azure Cloud Concepts

• Terminologies of the cloud: High Availability, Fault Tolerance, Disaster Recovery, Scalability, Elasticity, and Agility

High Availability

• If hardware fails, you can get a new, exact copy of it in very little time
• Use clusters (a group of virtual machines) to ensure high availability

Fault Tolerance

• Fault tolerance is part of the resilience of cloud computing
• Zero Down-Time –  if one component fails, a backup component takes its place

Disaster Recovery

• Plan to recover critical business systems:
  • Recovery Time Objective (RTO) is the time it takes after a disruption to restore business process to its service level
  • Recovery Point Objective (RPO) is the acceptable amount of data loss measured in time before the disaster occurs
• Services for backup and disaster recovery:
  • Azure Backup – simplify data protection while saving costs
  • Azure Site Recovery – keep your business running with disaster recovery service
  • Azure Archive Storage – store rarely used data in the cloud

Scalability

• You may increase or decrease the resources and services used at any given time, depending on the demand or workload.
  • Vertical Scaling – adding resources to increase the power of an existing server
  • Horizontal Scaling – adding more servers that function together as one unit

• Use scale sets for critical scenarios

Elasticity

• Quickly expand or decrease computing resources
• Automatically allocates more computing resources to handle the increased traffic. When the traffic begins to normalize, the cloud automatically de-allocates the additional resources to minimize cost

Agility

• The ability to design, test, and launch software applications quickly that stimulate business growth.
• Cloud agility enables companies to concentrate on other concerns such as security, monitoring, and analysis, instead of provisioning and maintaining the resources.