When I try to add a new NFS Volume to one of the ESXi hosts, I get NFS has reached the maximum number of supported volumes.

There is a long time that I don’t see this error(maybe since vSphere 5.5/6.0).

This means that the number of NSF volumes that are set in your ESXi host configuration has exceeded. By default, the maximum is 8.

These are the maximums that you can set in your ESXi host in Advanced configuration.

• ESXi/ESX 3.x     : Set NFS.MaxVolumes to 32
• ESXi/ESX 4.x     : Set NFS.MaxVolumes to 64
• ESXi 5.0/5.1/5.5 : Set NFS.MaxVolumes to 256
• ESXi 6.0/6.7/7.0 : Set NFS.MaxVolumes to 256

To fix this, we just need to go to the ESXi host that you receive the error, select Configuration tab, and in System – Advanced System Settings, edit and change the value for NFS.MaxVolumes.

Note: In filter in the right corner, type NFS to make it easy to find the option.

Changing the maximum volumes that are allowed in your ESXi host, you need also to check 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:

• • ESXi/ESX 3.x : Set Net.TcpipHeapMax to 120
  • ESXi/ESX 4.x: Set Net.TcpipHeapMax to 128
  • ESXi 5.0/5.1: Set Net.TcpipHeapMax to 128
  • ESXi 5.5: Set Net.TcpipHeapMax to 512

For ESXi 6.0 and ESXi 6.7, the default value for Net.TcpipHeapMax is 512M, and for ESXi 7.0, it is 1024M, which is sufficient and need not be increased further.  These settings enable the maximum number of NFS mounts for vSphere ESXi/ESX.

Note: Changing Net.TcpipHeapSize and/or Net.TcpipHeapMax requires a host reboot for the changes to take effect.

I hope this information was useful.

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