http://social.technet.microsoft.com/Forums/en-US/winserverhyperv/thread/6fb8cc70-bc52-4b3e-9aca-94288225a6ba

• In machine BIOS, disable C1E and C-States
• In machine BIOS, set all Power Management settings to “Maximum Performance”
• On NICs and switches, enable jumbo frames for connections to the storage, but leave regular MTU on connections to clustering network and LAN, DMZ, ecc (more on this below)
• On switches, disable all iSCSI optimizations
• On switches, disable Spanning Tree Protocol for all connections to storage
• Disable TCP Offloading and Receive Side scaling at the operating system level

  • C:\>netsh int tcp set global rss=disabled
    C:\>netsh int tcp set global chimney=disabled

• Verify which NICs among the ones you have available give the best performance to the storage. * On my machines (Dell PE R610) I have 4 onboard Broadcom NICs and an additional Intel quad port board and I have found that using the same settings, when connecting the storage via the Intel NICs performance are way better than the Broadcom (side note: right the opposite on VMware, much better via Broadcom)

Disable NetBIOS and Microsoft protocols on connections to the storage (obviously) Use as many NICs as possible to connect to the storage Install and configure iSCSI and MPIO using Dell MD Storage Software Verify that MPIO is set at Round Robin with Subset (MPIO tab on the disk properties in Server Management, Disk Management) Designate a preferred Network for Cluster Shared Volumes Communication:

 PS C:\> ( Get-ClusterNetwork "Storage Network 130" ).Metric = 500
 PS C:\> ( Get-ClusterNetwork "Storage Network 131" ).Metric = 501
 PS C:\> ( Get-ClusterNetwork "Storage Network 132" ).Metric = 502
 PS C:\> ( Get-ClusterNetwork "Storage Network 133" ).Metric = 503

Resulting settings

 PS C:\> Get-ClusterNetwork | ft Name, Metric, AutoMetric, Role
 Name                              Metric            AutoMetric                  Role
 ----                              ------            ----------                  ----
 Clustering Network                  1000                  True                     1
 Management Network                 10000                  True                     3
 Storage Network 130                  500                 False                     0
 Storage Network 131                  501                 False                     0
 Storage Network 132                  502                 False                     0
 Storage Network 133                  503                 False                     0

Install http://support.microsoft.com/kb/2517329/en-us Set the TCPAckFrequency to 1 on interfaces to the iSCSI storage, as explained in http://support.microsoft.com/kb/2020559/ and http://sustainablesharepoint.wordpress.com/2010/03/10/best-practice-for-hyper-v-with-iscsi/