Microsoft Hyper-V Performance Tuning

Microsoft Hyper-V

Performance Tuning

Jan Marek

Principle Architect

Cloud and Datacenter Platform Team Lead

Who’s Jan?

• v-guy 

• Hyper-V | App-V | MED-V | UE-V | Azure IaaS | VMware vSphere

• System Center

• Active Directory

• PowerShell

• MCSE | MCSA | MCITP | MCTS | MCT | MS

• Working with Hyper-V since it was Viridian 

• Microsoft MVP for Hyper-V

This talk is about

• Microsoft Hyper-V (Windows Server / Hyper-V Server)

• 2012 R2

• Performance Tuning of

• Host

Host (BIOS)

• Latest BIOS/UEFI firmware

Host (Hardware)

• Latest NICs firmware and drivers (but test, test and test!)

• Avoid disabling VMQ (dVMQ)

• Enable Jumbo Frames for CSV, iSCSI and LM networks

• Disable Non-iSCSI communication types on iSCSI NICs

• Don’t use NIC teaming for iSCSI NICs – use MPIO

• NIC teaming inside guest OS (sw-dep) should use SR-IOV NICs

• Use 4k native disks

• Use 64k allocation unit size for drives hosting VHD(X)

• Use auto-size for Page File

• Use processors with SLAT support and large cache

• Do NOT use MemoryReserve reg key

Use Parent Partition PerfMon

• Always measure the CPU usage of the physical system by using

the Hyper-V Hypervisor Processor performance counters

Host (OS)

• Core OS Edition

• Windows Update + Hotfixes

&

• Antivirus Exclusions

Host (Hyper-V)

• Only Hyper-V role

• VM Default Paths on non-system drive

• Avoid multiple Virtual Network Switches (use VLANs)

• Do NOT share adapter with physical OS

• Do NOT leave Hyper-V Manager running

• Leave Host NUMA enabled

VM

VM

Host

Host

NUMA n1

NUMA n2

_{NUMA n1}

_{NUMA n2}

Virtual Machine

Virtual Machine

Virtual Machine

• Dynamic Memory

Example 1 Example 2 Example 3 Example 4 Demand Buffer/Free Memory Left

Virtual Machine

• Dynamic Memory

1 hour 2 hours 3 hours 4 hours 5 hours 6 hours 7 hours 8 hours

High Weight

Minimum Demand Assigned

0 500 1000 1500 2000 2500 3000

1 hour 2 hours 3 hours 4 hours 5 hours 6 hours 7 hours 8 hours

Low Weight

Virtual Machine

• Use Legacy Network Adapter only for PXE boot (Gen 1)

• Remove unused vDevices (Gen 1)

hypervisor

hardware

VMbus

VSP

Driver

SYNTHETIC

LEGACY

Virtual Machine

Emulated 2 Synthetic

Virtual Machine

• Install and update IS

• Leave VM on logon screen + disable screen saver

• Do NOT use VMconnect as a standard to connect to VM

• Disable background activities:

• SuperFetch

• Windows Search

• Scheduled Tasks (Defrag,…)

Virtual Machine

• Avoid using DHCP Guard and Router Guard

• Don’t forget to turn off Port Mirroring after use

• For VLAN comm. use NICs with

NDIS_ENCAPSULATION_IEEE_802_3_P_AND_Q_IN_OOB encapsulation for

Large Send Offload and checksum offload

support

VM Storage

• Avoid CheckPoints

• Avoid vIDE for data disks (Gen 1)

• Use VHDX (instead of VHD or PT)

• Fixed VHDs are recommended

• Dynamic VHDXs are recommended

• Check VHD (not VHDX) data allignment

• Use ReFS in “Hyper-V vNext”

• Use Virtual HBAs only if needed

• Use Storage QoS

VM Storage

• Configure Advanced I/O balancer only if needed (reg)

HKLM\System\CurrentControlSet\Services\StorVsp\

\IOBalance_Enabled

HKLM\System\CurrentControlSet\Services\StorVsp\

\IOBalance_KeepHwBusyLatencyTarget_Microseconds

- how much work, represented by a latency value, the balancer allows to be issued to the hardware before throttling to provide better balance

- default is 83ms

HKLM\System\CurrentControlSet\Services\StorVsp\

\IOBalance_AllowedPercentOverheadDueToFlowSwitching

Cluster

• Use Hyper-V cluster only for Hyper-V HA services

• Separate Network Communication

• Mgmt | VM | LM | HB | CSV | iSCSI | Backup

• Set preferred network for CSV communication

• (Get-ClusterNetwork "Cluster Network 1").Metric = 700 (“< 1000”)

• Use CSV cache for read-oriented VMs (VDI)

• (Get-Cluster).BlockCacheSize = 1024

• LM: for >10Gbps use RDMA, for <10Gbps use compression

• LM: increase the number of send and receive buffers on each LM NIC

• Avoid using Low Priority VMs

SMB storage

• Use 10Gbps RDMA NICs

• Use Storage Spaces Write-Back Cache

• Async Hyper-V cluster is not supported

• Hosting SMB storage inside VM running on Hyper-V Cluster is

not supported

Thank you!

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