High Availability and Disaster Recovery

HIGH AVAILABILITY AND DISASTER RECOVERY

HIGH AVAILABILITY:

1. In simple words we can say that high availability refers to the availability of resources in a computer system.

2. In terms of cloud computing it refers to the availability of cloud services.

3. High availability is the heart of the cloud.

4. It provides the idea of anywhere, anytime access to service of cloud environment.

5. Availability is also related to reliability.

6. Availability is a technology issue as well as business issue.

7. High  Availability can be simply defined by the simple equation:



Where , 
MTBF – mean time between failures, 
MTTR- means time to repair and 
HA- high availability.

8. There is two way improve the availability:-
  1. Increase MTBF to very large values.
  2. Reduce MTTR to very low values.


DISASTER RECOVERY:

1. Disaster recovery (DR) is the process, policies and procedures that are related to preparing for recovery or continuation of technology infrastructure which are an organization after a natural or human-induced disaster.

2. A disaster recovery is the process by which an organization can recover and access their software, data, and hardware.

3. It is necessary for faster disasters recovery to have an infrastructure supporting high availability.

4. The failure of disaster recovery plan mainly due to lack of high availability preparation, planning and maintenance to occurrence of the disaster.

Strategies of Disaster Recovery:
  1. RTO (Recovery Time Objective): RTO is the period of time within which system, application, or functions must be discovered after an outage. RTOs are often used as the basis for the development of recovery strategies and as determinant as to whether or not to implement the recovery strategies during a disaster situation.
  2. RPO (Recovery point objective): RPO is the point to time to which systems and data must be recovered after an outage. RPOs are often used as the basis for the development of backup strategies, and as a determinant of the amount of data that may need to be recreated after the systems or function have been recovered.
More topics from Cloud Computing to read
Cloud Computing:
EasyExamNotes.com covered following topics in these notes.
  1. Introduction to Cloud Computing
  2. Historical development of Cloud Computing 
  3. Vision of Cloud Computing
  4. Characteristics of cloud computing as per NIST
  5. Cloud computing reference model
  6. Cloud computing environments
  7. Cloud services requirements
  8. Cloud and dynamic infrastructure
  9. Cloud Adoption and rudiments
  10. Cloud application: ECG Analysis in the cloud
  11. Cloud application: Protein structure prediction
  12. Cloud application: Gene Expression Data Analysis
  13. Cloud Computing Architecture
  14. IaaS
  15. PaaS
  16. SaaS
  17. Types of Clouds
  18. Cloud Interoperability & Standards
  19. Scalability and Fault Tolerance
  20. Cloud Ecosystem
  21. Cloud Business Process Management
  22. Cloud Service Management
  23. Cloud Analytics
  24. Testing Under Control
  25. Virtual Desktop Infrastructure
  26. Cloud Resiliency
  27. Cloud Provisioning
  28. Asset management
  29. Concepts of Map reduce
  30. Cloud Governance
  31. High Availability and Disaster Recovery
  32. Virtualization in cloud computing
  33. Server virtualization
  34. Hypervisor management software
  35. Third Party Cloud Services
  36. Case Study: Google App Engine
  37. Case Study: Microsoft Azure
  38. Case Study: Hadoop
  39. Case Study: Amazon
  40. Case Study: Aneka
A list of Video lectures
References:
  1. Buyya, Selvi ,” Mastering Cloud Computing “,TMH Pub
  2. Krutz , Vines, “Cloud Security “ , Wiley Pub
  3. Velte, “Cloud Computing- A Practical Approach” ,TMH Pub
  4. Sosinsky, “ Cloud Computing” , Wiley Pub
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Principles of Programming Languages
EasyExamNotes.com covered following topics in these notes.

Practicals:
Previous years solved papers:
A list of Video lectures References:
  1. Sebesta,”Concept of programming Language”, Pearson Edu 
  2. Louden, “Programming Languages: Principles & Practices” , Cengage Learning 
  3. Tucker, “Programming Languages: Principles and paradigms “, Tata McGraw –Hill. 
  4. E Horowitz, "Programming Languages", 2nd Edition, Addison Wesley

    Computer Organization and Architecture ↓ 👆

    Computer Organization and Architecture 

    EasyExamNotes.com covered following topics in these notes.

    1. Structure of desktop computers
    2. Logic gates
    3. Register organization
    4. Bus structure
    5. Addressing modes
    6. Register transfer language
    7. Direct mapping numericals
    8. Register in Assembly Language Programming
    9. Arrays in Assembly Language Programming

    References:

    1. William stalling ,“Computer Architecture and Organization” PHI
    2. Morris Mano , “Computer System Organization ”PHI

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    Computer Network

    EasyExamNotes.com covered following topics in these notes.
    1. Data Link Layer
    2. Framing
    3. Byte count framing method
    4. Flag bytes with byte stuffing framing method
    5. Flag bits with bit stuffing framing method
    6. Physical layer coding violations framing method
    7. Error control in data link layer
    8. Stop and Wait scheme
    9. Sliding Window Protocol
    10. One bit sliding window protocol
    11. A protocol Using Go-Back-N
    12. Selective repeat protocol
    13. Application layer
    References:
    1. Andrew S. Tanenbaum, David J. Wetherall, “Computer Networks” Pearson Education.
    2. Douglas E Comer, “Internetworking with TCP/IP Principles, Protocols, And Architecture",Pearson Education
    3. KavehPahlavan, Prashant Krishnamurthy, “Networking Fundamentals”, Wiley Publication.
    4. Ying-Dar Lin, Ren-Hung Hwang, Fred Baker, “Computer Networks: An Open Source Approach”, McGraw Hill.