TcpipHeapSize
and TcpipHeapMax
.Note: vSphere 6.0 has increased the maximum heap size and added support for the NFS 4.1 protocol. There are some differences between NFS3 and NFS4.1 support in vSphere 6.0. For more information, see the Understanding Network File System Datastores section of vSphere 6.0 Storage.
The vSphere ESXi/ESX default configuration allows for only eight NFS mounts per ESXi/ESX host. There are three advanced configuration options which control the maximum number of NFS mounts:
To edit advanced configuration options, select the ESXi/ESX host in the Inventory Panel, then navigate to Configuration > Software > Advanced Settings to launch the Settings window.
Select and highlight any of the advance options listed below the User Interface page will display, the range from Default to the Maximum value that can be set.
Set these values:
Modify the three advanced configuration options using the vSphere Client or other method. For a full list of methods, see Configuring advanced options for ESXi/ESX.
For more information on advanced NFS settings, see Definition of the advanced NFS options and the Best Practices For Running NFS with VMware vSphere whitepaper.
ESXi 6.5U3, 6.7U3 and 7.0:
In these releases, NFSv3 socket sizes are increased. Default socket size is 1MB(earlier 256K) for both send and receive sockets. Max that can be configured is 5MB(earlier 512K).
Default Net.TcpipHeapMax is increased to 1024MB. Max Net.TcpipHeapMax that can be configured is 3200MB.
Following equation gives the TCPIP heap required for number of shares.
TCPIPHeapMax required = shares * (send socket size + receive socket size)
Example 1:
Shares = 256. Socket size = 1MB (default)
TCPIPHeapMax required = 256 * (1M + 1M) = 512MB
So, for the default socket sizes of 1MB, existing default TCPIPHeapMax of 1024MB is sufficient.
Example 2:
Shares = 256. Configured Socket size = 5MB (NFS.SendBufferSize, NFS.ReceiveBufferSize)
TCPIPHeapMax = 256 * (5M + 5M) = 2560MB
In this case, one needs to increase the TCPIPHeapMax to atleast 2560MB.
These settings enable the maximum number of NFS mounts for vSphere ESXi/ESX.
Changing Net.TcpipHeapSize and/or Net.TcpipHeapMax requires a host reboot for the changes to take effect.
Possible Errors
2020-01-24T23:34:06.268Z cpu0:2099888 opID=4c099e1c)NFS: 205: NFS mount 1x.xxx.xxx.xx:/nfs_datastore failed: NFS has reached the maximum number of supported volumes
Maryam Suhana 07/11/2024
Removed the broken links from additional information section:
For translated versions of this article, see: