ICANWK525B Configure an Enterprise Virtual Computing Environment

ICTSUS5187A Implement Server Virtualisation for a Sustainable ICT system

Planning and Designing Server Virtualisation

An organisation has existing servers Issues: lots of power, low utilisation of

resources, cost of maintenance They are considering the feasibility of

virtualising these servers They have asked you to assess this

feasibility You need to write them a feasibility report

Planning to Virtualise Servers

Virtual servers need the same disk space as real ones

Virtual servers need roughly the same RAM (memory) as real ones

Virtual servers need the same bandwidth as real ones

Virtual servers, on average, only utilise about 15% to 20% of their CPU capacity

Things to Remember

You will either use the existing hardware, buy completely new hardware, or have a mix of old and new hardware

Given the 15-20% rule, plan for about 1/5 the number of equivalent CPUs◦ Less physical servers

However, same RAM requirements, so more RAM per physical server than before

Same disk requirements◦ Either more disks in each server, or a SAN

Same bandwidth, less servers => more or faster NICs per server. Even more so, if using SANs

Plan for Replacement Hardware

Ensure you can migrate VMs between physical servers, to allow you to have physical server downtime

Ensure flexibility to map drive space to all the VMs across all the physical servers

Ensure some spare capacity in case one physical server dies

Implication: some spare server CPU/RAM capacity

Implication: a SAN for the physical drives◦ Implication: more bandwidth and physical

infrastructure for the SAN

Plan for Redundancy & Flexibility

Baseline: measurement of the current system

I would measure over a week: Peak/average/minimum CPU usage per day Peak/average/minimum RAM usage per day Peak/average/minimum network bandwidth

per day Peak/average/minimum disk bandwidth per

day This will inform you as to the hardware and

networking capabilities of the new system

Take a Baseline

Ten existing servers, each with two quad-core Xeon CPUs, 8GB RAM, 2TB disk space

Connected to a switch with 10Gbps Ethernet ports

Baseline measurements:◦ 15% CPU utilisation, peaks at 100% on some servers for

a few minutes◦ Average RAM use: 6GB per server, peaks at 8GB but not

at same time across all servers◦ Network usage: two servers average 6 Gbps, the rest

average 1 Gbps, with occasional peaks of 5Gbps◦ Disk usage: at present, 14TB of the 20TB used◦ Disk bandwidth: average 3Gbps total, peaks to 5 Gbps

Example Scenario

Scale CPUs to 1/5: have only four quad-core Xeon processors

RAM: still need 10x6GB = 60GB, perhaps a bit more

Network: need at least 20Gbps Disk usage: need at least 14TB Disk bandwidth: need at least 5Gbps

Now, we have to spread this across the new physical servers

We want redundancy and flexibility

Example Scenario

2 or 3 servers: I would go for 3 servers◦ 2 can carry the load while one is down◦ Two quad-core Xeons per server => 6 Xeons not 4

RAM: 24GB per server times 3 = 72GB total

Bandwidth to the users: we need a 10Gbps multiport switch plus 7Gbps per server to the switch => go for 10Gbps NICs per server

Gives 30Gbps overall bandwidth

New Scenario

Storage Area Network (SAN):◦ RAID 6, we need 2 drives spare in an 8-drive array◦ Eight 3TB drives = 24TB, but only six 3TB = 18TB

usable

Bandwidth to the SAN: 2Gbps per server, so go for 10Gbps NICs◦ 3 NICs at 10Gbps is overkill

SAN device needs a 10Gbps NIC, plus a 10Gbps multiport switch to the servers

New Scenario

New Scenario

10 servers, now 3: power savings Redundancy with 3 servers: migrate VMs

if/when one server is down Need SAN device & associated

switch/cables May need new client-side switch Can we re-use some of the existing servers?

◦ Hard to tell without knowing the exact servers

Scenario Results & Questions

Feasibility report: is it feasible to virtualise the servers. Sections of the report:

Overview of the problem Analysis of existing hardware Baseline of existing system Recommendation of new design

◦ Advantages, disadvantages of new design◦ Ability to re-use existing infrastructure

Risk analysis: ◦ What could go wrong with the new design◦ What could go wrong during the transition

Will be a multi-page document, very formal

Feasibility Report

Feasibility given constraints: budget, time to complete, existing space etc.

You will need to give multiple options for new systems, plus the “null” option: do nothing◦ You can still mark one as the preferred option

Compare the advantages & disadvantages of each: cost, performance, risks.

Gives customer the ability to choose something that meets their organisational requirements and meets their constraints

Feasibility Report

The organisation has chosen one of the solution plans

Now it is design time Choose specific hardware to match the plan Choose specific virtualisation software Ensure existing customer server software

can be virtualised and migrated into VMs on the new system

Designing the Solution

VMware vSphere with ESXi Microsoft Hyper-V running Win Server 2012 Links:

◦ VMware: Comarison Against Hyper-V◦ InfoWorld: vSphere versus Hyper-V◦ Pay per Cloud: vSphere versus Hyper-V

Not just technical comparison, think of training, support, ease of management, ability to work with existing infrastructure◦ i.e the total cost of ownership (TCO)

The Main Server Virtualisation Products

Need to be able to migrate software on existing servers into VMs:◦ Operating system, applications, data stores

Both VMware and Hyper-V come with tools to do this:

VMware vCenter Converter Microsoft System Center Virtual Machine Ma

nager

Migrating Existing Servers to VMs

During your baseline, you should have done an audit of existing server operating systems and the application they are running◦ e.g. Windows Server 2008, Linux, web services

etc. Make sure any solution you choose can

virtualise these systems.◦ Both vSphere and Hyper-V can do Windows and

Linux vSphere has minimum

hardware requirements If chosen, make sure your design meets

these

Software & Hardware Requirements

Physical space, power, cooling If replacing an existing server system, you

will most likely need less space, power, cooling

However, during the transition, you may need more space, power, cooling◦ And the transition may take weeks

For both a new and a replacement build, you must determine the space, power and cooling requirement of the servers

Environmental Considerations

Server room design is out of scope for this unit. Some useful links:

M.Moser: Server Room Design UC Davis: Server Room Best Practices Requirements for the Design of ICT Rooms

Environmental Considerations