At VSphere 5.1 Client. I was able to see the Dual-Port Network Adapter (vmnic22.p1, vmnic22.p2) after I install the Vmware  Installing Mellanox ConnectX® EN 10GbE Drivers for VMware® ESX 5.x Server.

But somehow I am not able to use the 2nd port of the Mellanox ConnectX 10G on the VSphere Client > Configuration > Networking. It will not be visible. However at the VSphere Client > Configuration > Networking > Add Networking, I not able to see the 2nd Port being available.

I found the document from Mellanox (MellanoxMLX4_ENDriverforVMwareESXi-5.xREADME) which is useful to resolve the issue. At Page 10,

Adding the Device as an uplink to an Existing Vswitch using the CLI

Step 1: Log into the ESXi server with root permission

Step 2: Add an uplink to a vswitch, run:

# esxcli network vswitch standard uplink add –u <uplink_name> -v <vswitch_name>

* Uplink_name refer to the name used by ESX for the network Adapter. For example, vmnic22.p2 is the uplink name

Step 3: Check that uplink was added successfully. Run:

# esxcli network vswitch standard list -v <vswitch_name>

Removing the Device an an uplink to an Existing Vswitch using the CLI

Step 1: Log into the ESXi server with root permissions

Step 2: Remove an uplink from a vswitch, run:

# esxcli network vswitch standard uplink remove -u <uplink_name> -v <vswitch_name>

Do read the Blog Entry Installing Mellanox ConnectX® EN 10GbE Drivers for VMware® ESX 5.x Server

Step 1: At VMware ESX 5.x Hypervisor,

• Click the F2 button
• Select “Troubleshoot Options”
• “Enable ESXi Shell” and “Enable SSH”

Step 2: Download the VMware ESXi 5.0 Driver for Mellanox ConnectX Ethernet Adapters

Step 3: Unzip the mlx4_en-mlnx-1.6.1.2-offline_bundle-471530.zipEdit

Step 4: The upgrade process is similar to a new install, except the command that should be issued is the following:

#   esxcli software vib upgrade -v {VIBFILE}

In the example above, this would be:

#  esxcli software vib update -v 
/tmp/net-mlx4-en-1.6.1.2-1OEM.500.0.0.406165.x86_64.vib

If you have Mellanox Technologies MT27500 Family [ConnectX-3] 10G Ethernet Card, it may not be automatically detected by VMware ESX 5.x Hypervisor. You have to install the driver manually into Vmware 5.x

Step 1: At VMware ESX 5.x Hypervisor,

• Click the F2 button
• Select “Troubleshoot Options”
• “Enable ESXi Shell” and “Enable SSH”

Step 2: Download the VMware ESXi 5.0 Driver for Mellanox ConnectX Ethernet Adapters

Step 3: Unzip the mlx4_en-mlnx-1.6.1.2-offline_bundle-471530.zip

Step 4: Read the README file

VMware uses a file package called a VIB (VMware Installation Bundle) as the  mechanism for installing or upgrading software packages on an ESX server.

The file may be installed directly on an ESX server from the command line, or through the VMware Update Manager (VUM).

Step 5:  For New Installation (From README and modified)

For new installs, you should perform the following steps:

Step 5a: Copy the VIB to the ESX server.  Technically, you can place the file anywhere that is accessible to the ESX console shell, but for these instructions, we’ll assume the location is in ‘/tmp’.

Here’s an example of using the Linux ‘scp’ utility to copy the file from a local system to an ESX server located at 10.10.10.10:

# scp net-mlx4-en-1.6.1.2-1OEM.500.0.0.406165.x86_64.vib root@10.10.10.10:/tmp

Step 5b: Issue the following command (full path to the VIB must be specified):

# esxcli software vib install -v {VIBFILE}

In the example above, this would be:

# esxcli software vib install -v 
/tmp/net-mlx4-en-1.6.1.2-1OEM.500.0.0.406165.x86_64.vib