Ridi Ferdiana | ridi@acm.org Version 1.0.0

Availability is the process of optimizing the readiness of information systems by accurately measuring, analyzing, and reducing outages to information systems.

Similarity

Measured by time in a year / month

The difference

Uptime is a measure of the time that individual components within a production system are functionally operating

Availability focuses on the production system as a whole.

Data Center Facility

Server Hardware

Server System

Software

Application Software

Disk Hardware

Database Software

Network Software

Network Hardware

Desktop Software

Desktop Hardware

Slow response refers to unacceptably long periods of time for an online transaction to complete processing and return results to the user

Downtime refers to the total inoperability of a hardware device, a software routine, or some other critical component of a system that results in the outage of a production application.

High availability refers to the design of a production environment such that all single points of failure are removed through redundancy to eliminate production outages

Fault tolerant refers to a production environment in which all hardware and software components are duplicated such that they can automatically failover to their backup component in the event of a fault

Hig

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ility

Fault Tollerant

Availability

Up Up

Redudancy Redudancy

Percent Availability = (Hours Agreed Up - Hours Down)/Hours Agreed Up

Budget limitations

Component failures

Faulty code

Human error

Flawed design

Natural disasters

Unforeseen business shifts (such as mergers, downturns, political changes)

Redundancy Power supplies

Multiple processors

Segmented memory

Redundant disks

Reliability Logs

Management Feedback

Analyst

Recoverability Network Avail.

System Restart

System Switch Over

Repairability MTBF = sampling interval / # of failures during sampling interval

MTTR = sum of repair times / # of failures

Reputation Percent market share

Industrial comment

Publication

Review Track records

Customer Reference

Responsiveness In house support

Recovery disk

Well trained user

Robustness Technical changes: Platform, Product, Services, Customer

Personal changes: Turnover, Expansion, Rotation

Business changes: New direction, Acquisitions, Merger

Learning the key terms : Availability, Up Time, Fault Tolerant, and High Availability

10 key components of high availability

Key skills that needed to handle the IS Availability

Measuring Availability from SLA

High Availability Limitation

7 Rs of Availability

Assesing Availability