Objective 3.1 – Tune and Optimize vSphere Performance

Knowledge - Identify appropriate BIOS and firmware setting requirements for optimal ESXi host performance

Performance Best Practices for VMware vSphere™ 5.0

Knowledge - Identify appropriate driver revisions required for optimal ESXi host performance
Ensure you are using the most up-to-date firmware for your host.

Ensure vendor drivers are added where available such as HP bundle for ESXi or the OEM version of ESXi.

Check for any available plugins for vCenter eg NetApp VSC for configuring LUN multipathing and queue depths.

Skills and Abilities - Tune ESXi host memory configuration

• Enable NUMA
• Enable Rapid Virtualization Indexing (AMD) or Extended Page Tables (Intel) 
• Disable Node Interleaving
• Disable disable memory pre-fetching (for specific memory use profiles only)

Skills and Abilities - Tune ESXi host networking configuration
Virtual machine networking can have a big overhead on host CPU

• Enable Netflow and analyse output from the collector
• Adjust queue depths \ TCP offloads
• Enable Jumbo Frames for network based storage and vMotion network.
  
• When specifying NICs look for 10g PCIe network cards with NetQueue feature.
  
• Use multiple uplinks
• Configure Network IO flow control to tune network traffic.
  

Skills and Abilities - Tune ESXi host CPU configuration

• Enable Turbo Boost (where available)
• Enable “C-states” to save more power, and can make Turbo Boost more effective.
• Enable Hyperthreading (where available)
• Enable Hardware Assisted Virtualization (Intel VT-x and AMD-V)
• Set CPU power to “OS Control” in BIOS.

Identify if any VMs use graphics extensively and whether you might want to add dedicated GPU. (only benefit 5.1 onwards)


Skills and Abilities - Tune ESXi host storage configuration
Understand your VM workload with vscsiStat and depending on your workload characteristics you may, or may not, tune storage for read or write cache.

Ensure HBA configuration is set as per SAN vendor settings.

Ensure your storage array firmware is updated to take advantage of VAAI.

If using NFS storage ensure any VAAI for NFS plugins are installed.

Look at FusionIO PCIe modules,  or using SSD and software such as that from PernixData to use local SSD as read and\or write cache.

Enable storage DRS and storage IO control

Skills and Abilities - Configure and apply advanced ESXi host attributes



Skills and Abilities - Configure and apply advanced Virtual Machine attributes
vSphere client -> Inventory -> VM -> Right-click and select Edit Settings…
    Options -> General -> Configuration Parameters

By default in vSphere 5.0 a VMX swap file is created when each virtual machine is powered on. This is created in the virtual machine’s working directory,  the location can be changed using sched.swap.vmxSwapDir. Although not recommended, the VMX swap feature can be disabled on a virtual machine by setting sched.swap.vmxSwapEnabled to FALSE,  by disabling this reduces the size of VMX memory reservation from about 50MB or more per virtual machine to about 10MB per virtual machine with no noticeable performance impact. See more detail here

Always right-size your VMs,idle vCPU wastes resources and VMs can always be increased in size if necessary, whereas an oversized VM will not get the attention required to change the size at a later date.

Where possible use 1 vCPU per virtual socket, putting multiple cores per virtual socket can impact performance in NUMA systems.

Enable vNUMA where possible,  gives up to 70% performance improvement over non-vNUMA.  Further details here

When a virtual machine is powered on for the first time, a new swap file is created in the working directory of the virtual machine. By default, the virtual machine writes the swap file in the same directory as the.vmx configuration file. If you would like to change this location, add the new location to this line in the.advanced VM configuration.
     sched.swap.dir = "path_to_vm_directory"

SplitRx mode typically improves throughput and CPU efficiency for multicast traffic workloads.  SplitRx mode is supported only on vmxnet3 network adapters. This feature is disabled by default. Enabling SplitRx Mode in situations where multiple virtual machines share a single physical NIC and receive a lot of multicast or broadcast packets.

Skills and Abilities - Configure advanced cluster attributes
Turn on and configure DRS and HA,  consider changing HA slot size but only do so if your totally sure your changing it correctly.

DRS Power Management
VMware HA VM Monitoring
VMware Datastore Heatbeating
EVC
Swapfile Location.......