- Explain the common components of logical design.
The common components of a Logical Design are:
- Focuses on satisfying the design factors (requirements, risks, constraints assumptions)
- relationships between all major infrastructure components
- How to arrange components
- Does not contain physical detail like ports or ip addresses etc
Image below is an example of a logical design, very simple and clearly shows servers running vSphere running VMs which is all managed by vCenter.
- List the detailed steps that go into the makeup of a common logical design.
- Step one – Gather information from various sources (stakeholder interviews, current state analysis and any exisiting documentation)
- Step two – Define Requirements
- Goals (why and when)
- Scope (What and what not)
- Constraints (must have or must not have)
- Risks (what will stop this from happening)
- Assumptions (Already have but is not backed by any evidence )
- Requirements – Functional ( what the system must do )
- Requirements – Non Functional (behaviour of system)
- Step three – Determine dependencies (what and who is affected by this project)
- Step four – Create conceptual design that meets the goals and requirements.
- Step five – Project approves the above
- Step Six – Create the Logical Design.
- Differentiate functional and non-functional requirements for the design.
- Functional Requirement – What the system or project must do. for example all service desk staff must be able to reboot and console into the virtual machines.
- Non Functional – also can be considered a constraint that’s been placed on the project by the client. for example – vitrual machine storage must use the existing NetAPP iSCSi storage and have less than 10ms latency.
Skills and Abilities
- Build non-functional requirements into a specific logical design.
Below I have put in the above non functional design of having to use the existing iSCSI storage.
- Translate given business requirements and the current state of a customer environment into a logical design.
Same as above take a business requirement function or non functional and give a high level design. for example the new project needs to take the current site and provide fail-over to a remote site with SAN replication, here we just show how it should work with no details on what technology or how we are going to do it.
- Create a Service Catalog
A service catalog is introduced from ITIL and should contain the following
- Service name (Extended Support)
- Service description (Maintenance and support of servers and components)
- Services included (Patch management, upgrades, incident support)
- Services not included (Non-standard changes)
- Services availability (24x7x365)