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Compare and contrast physical and virtual hardware resources

February 1, 2013 Objective 3 Tuning and Optimisation No comments

Before Virtualisation

  • Single O/S Image per machine
  • Software and Hardware tightly coupled
  • Running multiple applications on the same machine can create conflicts
  • Underutilised resources
  • Inflexible and costly infrastructure
  • Datacenter space taken up in multiple physical servers
  • High Management, Support and Operating costs

Physical

After Virtualisation

  • Hardware independence of operating system and applications
  • Virtual machines can be provisioned to any system
  • Can manage OS and application as a single unit by encapsulating them into virtual machines
  • Power Savings
  • Rack space savings
  • Feature rich flexibility (vMotion, Storage vMotion, DRS, HA)
  • Rapidly provision test and development servers

Virtual

Virtual Infrastructure now

While virtualization has been a part of the IT landscape for decades, it is only recently (in 1998) that VMware delivered the benefits of virtualization to industry-standard x86-based platforms which now form the majority of desktop, laptop and server shipments. A key benefit of virtualisation is the ability to run multiple O/S’s on a single virtual system and share the underlying hardware resource

There are 2 types of architecture – Hosted architecture (VMware Workstation) and Bare metal Architecture (ESX/ESXi)

We can now take advantage of features such as

  • The latest generation of x86-based systems feature processors with 64-bit extensions supporting very large memory capacities. This enhances their ability to host large, memory-intensive applications, as well as allowing many more virtual machines to be hosted by a physical server deployed within a virtual infrastructure.
  • The VMKernel runs individual VMMs for each VM responsible for the execution of the VM
  • The VMM which is a thin layer providing virtual x86 hardware to the overlying O/S including memory management, CPU scheduling, networking and storage
  • Hardware Assist (Intel VD and AMD V)
  • Paravirtualisation hardware
  • DirectPath
  • Direct Memory Access
  • AMD RVI and Intel EPT
  • Emulated Hardware
  • DRS
  • HA
  • sDRS
  • I/O Control for Networking and Storage
  • NPIV
  • Passthrough devices
  • Shares, Reservations and Limits
  • Resource Pools
  • Clustered file system VMFS
  • Raw Disk Mappings
  • 3 Virtual Disk types (Eager zeroed thick, Lazy Zeroed thick and Thin)
  • Memory reclamation techniques