Tag Archives: ITIL

VDCD510 Objective 2.5 – Build Performance Requirements into the Logical Design

Identify Infrastructure Qualities
We have already covered infrastructure qualities in objective 2.3. To recall them, here is a short overview:

Availability is the ability of a system or service to perform its required function when required. It is usually calculated as a percentage like 99,9%.
Manageability describes the expense of running the system. If you have a huge platform that is managed by a tiny team the operational costs are very low.
Performance is the measure of what is delivered by a system. This accomplishment is usually measured against known standards of speed completeness and speed.
Recoverability describes the ability to return a system or service to a working state. This is usually required after a system failure and repair.
Security is the process of ensuring that services are used in an appropriate way.

 

Key Performance Indicators
According to ITIL, a Key Performance Indicator (KPI) is used to assess if a defined service is running according to expectations. The exact definition of the KPIs differs depending on the area. This objective is about server performance which is typically assessed using the following KPIs: Processor, Memory, Disk, and Network. VMware offers several concepts for managing resources.

Processor
To manage CPU resources VMware relies on the the CPU scheduler. The CPU scheduler shares the same logical processor among multiple virtual machines. It defines the following terms:

  • Processor Socket: A physical CPU
  • Core: A logical core within a physical CPU
  • Logical Processor: A hyperthreading CPU Core presents itself as multiple logical processors

Memory
VMware offers the following features to manage the memory efficiently

  • Transparent Page Sharing: Shares identical Memory Pages among multiple virtual machines. This feature is active by default and does not impact the performance of the virtual machine.
  • Ballooning: Controls a balloon driver which is running inside each virtual machine. When the physical host runs out of memory it instructs the driver to inflate by allocating inactive physical pages. The ESX host can uses these pages to fulfill the demand from other virtual machines.
  • Memory Compression: Prior to swap memory pages out to physical disks the ESX server starts to compress pages. Compared to swapping, compression can improve the overall performance in an memory overcommitment scenario.
  • Swapping: As the last choice the ESX hypervisor starts to swap pages out to physical disks. This is definitely a bad situation as disk are much slower than memory.

Disk
Storage I/O Control (SIOC) allows cluster wide control of disk resources. The main goal is to prevent a single VM to use all available disk performance from a shared storage. With SIOC a virtual machine can be assigned a priority when contention arises on a defined datastore.

Network
Network I/O Control (NetIOC) enables traffic prioritization by partitioning of network bandwidth among the entire cluster.

 

VCAP5-DCD Exam Blueprint v1.1

Knowledge

  • Understand what logical performance services are provided by VMware solutions.
  • Identify and differentiate infrastructure qualities (Availability, Manageability, Performance, Recoverability, Security)
  • List the key performance indicators for resource utilization.

Skills and Abilities

  • Analyze current performance, identify and address gaps when building the logical design.
  • Using a conceptual design, create a logical design that meets performance requirements.
  • Identify performance-related functional requirements based on given non-functional requirements and service dependencies.
  • Define capacity management practices and create a capacity plan.
  • Incorporate scalability requirements into the logical design.
  • Determine performance component of SLAs and service level management processes.

Tools

Back to VCAP5-DCD Study Guide

VDCD510 Objective 2.4 – Build Manageability Requirements into the Logical Design

Identify Infrastructure Qualities
We have already covered infrastructure qualities in objective 2.3. To recall them, here is a short overview:

Availability is the ability of a system or service to perform its required function when required. It is usually calculated as a percentage like 99,9%.
Manageability describes the expense of running the system. If you have a huge platform that is managed by a tiny team the operational costs are very low.
Performance is the measure of what is delivered by a system. This accomplishment is usually measured against known standards of speed completeness and speed.
Recoverability describes the ability to return a system or service to a working state. This is usually required after a system failure and repair.
Security is the process of ensuring that services are used in an appropriate way.

Event, Incident and Problem Management
This concept is related to the well known ITIL standard.

Event: A change of state which might have an influence for the management of a service or system
Incident: An event which is not part of the standard operation. It might cause a service disruption or reduce the productivity.
Problem: The cause of one or more incidents. Problems are usually identified because of multiple incidents.

Please note that an incident might give a hint to the investigation of a Problem, but never become a Problem. Even if the incident is elevated to the 2nd level, it remains an incident. The problem management might manage the resolution of the incident when the incident can only be closed by solving the Problem.

Change Management
The change management process is responsible for controlling the lifecycle of all changes. Changes are defined as the addition, modification or removal of anything that could have an effect to services or systems. The primary objective of change management is to enable beneficial changes to be made, with minimum disruption.

VCAP5-DCD Exam Blueprint v1.1

Knowledge

  • KnowledgeUnderstand what management services are provided by VMware solutions.
  • Identify and differentiate infrastructure qualities (Availability, Manageability, Performance, Recoverability, Security)

Skills and Abilities

  • Build interfaces to existing operations practices into the logical design
  • Address identified operational readiness deficiencies
  • Define Event, Incident and Problem Management practices
  • Define Release Management practices
  • Determine Request Fulfillment processes
  • Design Service Asset and Configuration Management (CMDB) systems
  • Define Change Management processes
  • Based on customer requirements, identify required reporting assets and processes

Tools

Back to VCAP5-DCD Study Guide