Connection sharing with NFS41 mounts

Products

• VMware vSphere ESXi

Issue/Introduction

This KB details different scenarios of connection sharing with NFS41 mounts

Environment

VMware vSphere ESXi 6.x

VMware vSphere ESXi 7.x

VMware vSphere ESXi 8.x

Resolution

• Each NFS41 server instance is identified by a server_owner which is a combination of server_major and server_minor and uniquely identifies a server in a cluster.
• When an NFS41 client mounts a share, it creates a session per server_owner and associates the TCP connection with the session.
• Since a session is already created, if another datastore gets mounted from the same sever instance, the new datastore gets associated with the same session and hence reuses the same TCP connection.

1. Example with one path:
esxcli storage nfs41 add -H IP1 -v share1 -s share1
esxcli storage nfs41 add -H IP1 -v share2 -s share2

In the above example,"share2" will use the same TCP connection created as part of mounting "share1"

2. Example with multipathing:
esxcli storage nfs41 add -H IP1, IP2 -v share1 -s share1
esxcli storage nfs41 add -H IP1 -v share2 -s share2

In the above example,"share2" will use both the TCP connections, IP1 and IP2, created as part of mounting "share1"

3. Examples with nConnect:
esxcli storage nfs41 add -H IP1 -v share1 -s share1 -c 2
esxcli storage nfs41 add -H IP1 -v share2 -s share2

In the above example,"share2" will use both the TCP connections, created as part of mounting "share1"

esxcli storage nfs41 add -H IP1 -v share2 -s share2 -c 2

In the above example,"share2" will use the two existing TCP connections created as part of mounting "share1" i.e. no new connections are created

Note: "nConnect" is available only from 8.0 U3b

Additional Information

NFS Protocols and ESXi
Best Practices For Running NFS with VMware vSphere
Guidelines and Requirements for NFS Storage with ESXi