NFS Advanced Settings and vCheck
While working on a new plugin for the popular vCheck tool, I wanted to find the most common recommendations for the ESXi advanced settings pertaining to NFS/NAS datastores. I knew that these varied some based on the storage vendor, but thought there might be enough common ground to offer some sensible defaults in the plugin. I found that some of the settings can also vary based on ESXi version and in the end I erred on the side of caution and submitted the plugin as disabled by default. My thought process here was to insure that a vSphere Admin needs to actively configure it and it won’t make sub-optimal recommendations for some environments and not others. This post is mostly to summarize what I found and list what I thought were some of the more useful references.
I created a table to easily compare the settings based on ESXi version and vendor.
| Setting | ESXi 6.0u3 Defaults | ESXi 6.5 Defaults | VMware KB 2239 | VMware Whitepaper | NetApp | Tintri | Oracle |
|---|---|---|---|---|---|---|---|
| Net.TcpIpHeapSize | 0 | 0 | 32 | - | 32 | See KB 2239 | 32 |
| Net.TcpIpHeapMax | 512 | 512 | 1536 | - | 512 | See KB 2239 | 512 |
| NFS.MaxVolumes | 8 | 8 | 256 | - | 256 | See KB 2239 | 256 |
| NFS.HeartbeatMaxFailures | 10 | 10 | - | 10 | 10 | 10 | 10 |
| NFS.HeartbeatFrequency | 12 | 12 | - | 12 | 12 | 12 | 20 |
| NFS.HeartbeatDelta | 5 | 5 | - | - | - | - | 12 |
| NFS.HeartbeatTimeout | 5 | 5 | - | 5 | 5 | 5 | 5 |
| NFS.SendBufferSize | 264 | 264 | - | - | - | - | 264 |
| NFS.ReceiveBufferSize | 256 | 256 | - | - | - | - | 256 |
To keep the table simple I only included the settings for vSphere/ESXi 6.0 and up. ESXi 5.5 and lower have lower recommendations for some of the settings. Consult the references linked below for details.
References:
- KB 2239: Increasing the default value that defines the maximum number of NFS mounts on an ESXi/ESX host (2239)
- VMware: Best Practices for Running VMware vSphere® on Network-Attached Storage (NAS)
- NetApp: VMware vSphere with ONTAP (NetApp)
- Tintri: Tintri VMstore with VMware Best Practices Guide
- Oracle: Best Practices for Configuring Oracle ZFS Storage Appliance and VMware vSphere 6.x with NFS Protocol
A couple of other good articles - this one is now somewhat dated (2009), but still very useful: A “Multivendor Post” to help our mutual NFS customers using VMware
A newer post (2015) including information on vSphere 6 and NFS 4.1 support: Best Practices running VMware with NFS
One thing I think everyone can agree on is that it’s important to have all of your hosts configured the same. If you’re interested in using vCheck to report on this download the latest version and enable the “Host NFS Settings” plugin.
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