Availability Management

Availability Management

- Premanand Lotlikar 31st July, 2007

Agenda • • • • • • • • • •

Introduction Objective of Availability Mgmt Basic Concepts Benefits Relationship with other processes Activities in Change Mgmt Process Control Key Performance Indicators Cost Possible Problems

Objectives • Determining availability requirements in close collaboration with customers • Guaranteeing the level of availability established for the IT services • Monitoring the availability of the IT services • Proposing improvements in the IT infrastructure and services with a view to increasing levels of availability • Supervising compliance with the OLAs and UCs agreed with internal and external service providers

Basic Concepts

Basic Concepts • High Availability means – IT service is continuously available to the customer – Little downtime – Rapid service recovery

• Availability of service depends on – – – –

Complexity of the IT infrastructure architecture Reliability of the components Ability to respond quickly and effectively to faults Quality of maintenance by support and suppliers

Basic Concepts • Reliability means – Service is available for an agreed period without interruptions

• Includes resilience • Calculated using statistics • Determined by – Reliability of the components – Ability of service/component to operate despite failure (resilience) – Preventive maintenance

Basic Concepts • Maintainability needed to – Keep the services in operations – Restore services when they fail

• Includes – Taking measures to prevent faults – Detecting faults – Making diagnosis by components themselves – Resolving the fault – Restoring the service

Basic Concepts

Basic Concepts • Mean Time to Repair (MTTR) – Avg time b/w the occurrence of a fault and service recovery

• Mean Time Between Failures (MTBF) – Avg time b/w recovery from one incident and the occurrence of next

• Mean Time Between System Incidents (MTBSI) – Avg time b/w the occurrence of two consecutive incidents

Benefits • Fulfillment of the agreed service levels. • Reduction in the costs associated with a given level of availability. • The customer perceives a better quality of service. • The levels of availability progressively increase. • The number of incidents is reduced.

Inputs - Outputs

Relationship with other processes • Service Level Mgmt is responsible for negotiating & managing availability • Availability is one of the most important element in SLA

Relationship with other processes • Configuration Mgmt has information about the infrastructure and can provide valuable information to Availability Mgmt

Relationship with other processes • Changes in capacity can often affect the availability of a service • Changes to availability will affect capacity • These 2 processes exchange info about – Scenarios for upgrading – Phasing out IT components – Availability trends that may need changes to capacity

Relationship with other processes • Problem Mgmt is directly involved in identifying and resolving the causes of actual or potential availability problems

Relationship with other processes • Incident Mgmt provides reports with information about recovery times, repair times etc. This information is used to determine the achieved availability.

Relationship with other processes • Change Mgmt informs Availability Mgmt about FSC • Availability Mgmt informs Change Mgmt about maintenance related to new service and elements.

Activities • Planning • Monitoring

Planning • • • • • •

Determining the availability requirements Designing for availability Designing for recoverability Security issues Maintenance management Developing the Availability Plan

Determining the availability requirements • Must be undertaken before SLA is concluded • Should address both new IT services and changes to existing services • Clearly defining availability requirements early is essential to prevent confusion and differences

Determining the availability requirements • Should identify: – Key business functions – Agreed definition of IT service downtime – Quantifiable availability requirements – Quantifiable impact on the business functions of unscheduled IT service downtime – Business hours of customer – Agreements about maintenance windows

Designing for availability • Vulnerabilities affecting availability standards should be identified early • This will prevent – Excessive development costs – Unplanned expenditure at later stages – Additional cost by suppliers – Overall delays

Designing for recoverability • Uninterrupted availability is rarely feasible • Design for recoverability involves – Effective Incident Mgmt – Appropriate escalation – Communication – Backup and recovery procedures – Tasks, responsibilities and authority clearly defined

Key Security issues • Security and reliability are closely linked • High availability can be supported by effective information security • This includes: – Determining who is authorized to access secure areas – Determining which critical authorizations may be issued

Maintenance management • There will always be scheduled window of unavailability • These periods can be used for preventive actions • Maintenance must be carried out when impact on services can be minimized

Developing the Availability Plan • Long term plan concerning availability over the next few years • It is not the implementation plan for Availability Mgmt • Plan require liaison with areas such as – Service Level Mgmt – IT Service Continuity Mgmt – Capacity Mgmt – Change Mgmt

Methods and Techniques • Component Failure Impact Analysis(CFIA) – Uses an Availability matrix with strategic components and their roles in each service – Horizontal Analysis – Vertical Analysis

CFIA

Fault Tree Analysis • Used to identify chain of events leading to failure of IT service • Distinguishes following events: – Basic Event: power outages or operator error – Resulting Event: resulting from combination of earlier events – Conditional Event: events that occur only in certain conditions – Trigger Event: events that cause other events

Fault Tree Analysis

Availability Calculations • Availability is commonly defined as a percentage as follows: • For example, if the service is 24/7 and over the last month the system has been down for four hours to carry out maintenance, the real availability of the system was:

Process Control • Critical Success Factors – Business must have clearly defined availability objectives – SLM must have been setup to formalize agreements – Both parties must use the same definitions of availability and downtime

Process Control • Key Performance Indicators – Percentage availability per service – Downtime duration – Downtime frequency

Cost

Possible Problems • The real availability of the service is not monitored correctly. • There is no commitment to the process in the IT organization. • The appropriate software tools and personnel are not available. • The availability objectives do not match the customer's needs. • There is a lack of coordination with other processes. • Internal and external service providers do not recognize the authority of the Availability Manager as a result of a lack of support from management

Thank you!