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Increasing the default value that defines the maximum number of NFS mounts on an ESX/ESXi host

Details

This article describes how to change the default value for the configuration parameter that defines the maximum number of NFS mounts on an ESX/ESXi host.

Specifically, this article discusses:

  • Configuring NFS TCP and NFS HEAP settings
  • Identifying appropriate settings for TcpipHeapSize and TcpipHeapMax.

Solution

Default configuration of vSphere ESX allows for only eight NFS mounts per ESX host. There are three advanced configuration options which control the maximum number of NFS mounts:

To edit advanced configuration options, select the ESX host in the Inventory Panel, then go to the Configuration tab > Software > Advanced Settings to launch the Settings window.

Set these values:

  • NFS.MaxVolumes: Limits the number of NFS Datastores which can be mounted by the vSphere ESX/ESXi host concurrently. The default value is 8, and can be increased to a maximum specific to the version of ESX/ESXi:

    • ESX/ESXi 3.x: Set NFS.MaxVolumes to 32
    • ESX/ESXi 4.x: Set NFS.MaxVolumes to 64
    • ESXi 5.0; Set NFS.MaxVoumes to 256

  • Net.TcpipHeapSize: The amount of heap memory, measured in megabytes, which is allocated for managing VMkernel TCP/IP network connectivity. When increasing the number of NFS Datastores, increase the default amount of heap memory as well:

    • ESX/ESXi 3.x: Set Net.TcpipHeapSize to 30
    • ESX/ESXi 4.x: Set Net.TcpipHeapSize to 32
    • ESXi 5.0: Set Net.TcpipHeapSize to 32

  • Net.TcpipHeapMax: The maximum amount of heap memory, measured in megabytes, which can be allocated for managing VMkernel TCP/IP network connectivity. When increasing the number of NFS Datastores, increase the maximum amount of heap memory as well, up to the maximum specific to the version of ESXi/ESX host.

    • ESX/ESXi 3.x : Set Net.TcpipHeapMax to 120
    • ESX/ESXi 4.x: Set Net.TcpipHeapMax to 128
    • ESXi 5.0: Set Net.TcpipHeapMax to 128

    Note: These settings enable the maximum number of NFS mounts for vSphere ESX/ESXi.   

Modify the three advanced configuration options using the vSphere Client or other method. For a full list of methods, see Configuring advanced options for ESX/ESXi (1038578).

For more information on advanced NFS settings, see Definition of the advanced NFS options (1007909) and the Best Practices for running VMware vSphere on Network Attached Storage whitepaper.

Tags

NFS-advanced-options

Keywords

NFS, mounts, host, ESX, ESXi, TcpIpHeapSize, TcpIpHeapMax

Update History

11/07/2011 - Updated values

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