What is the difference between ESXi inbox driver and ESXi async driver

 VMware ESXi is a hypervisor software that allows users to create virtual machines (VMs) on physical hardware.

An ESXi driver is a software component that enables the use of a specific device or resource for VMware ESXi.

The ESXi inbox drivers are shipped with ESXi.

ESXi async drivers are developed by hardware vendors or third-party vendors.  They are not bundled with the ESXi software.  They are usually downloaded from Broadcom website and then installed.

When an async driver is installed, the inbox driver is not removed.  This results in more than one driver being installed for the same device.

When both inbox and async drivers are present, both are displayed as installed.  However, only one of them is loaded and is in use.

How to determine which drivers are installed

# esxcli software vib list | less

# esxcli software vib list | egrep <driver_name>

Note : If both inbox and async driver are installed, the above grep command displays both

How to determine which drivers are in use

# esxcfg-info | less

In case of network drivers :

# ethtool -i vmnicX

To identify the vmnic # of the associated NIC :

# esxcfg-nics -l

# esxcli network nic get -n vmnicX

Should you use ESXi inbox driver or the ESXi async driver

Obviously, there is no simple answer to this question.  A careful review of the situation should help to come to a decision.

Factors to be considered could be :

• Is the hardware vendor doing active development and fixing many issues in the async driver?
• Do you want to use a native driver or a vmklinux driver?  And why?
• Comparing the release notes of the inbox driver and async driver, do you see a pattern?
• Which one seems to be more stable?
• Which one seems to be more actively maintained?

Although this review may take a long time, making this informed decision may avoid an outage or an unpleasant situation in the future.