If you boot from SAN using iBFT and your ESXi host does not have a local diagnostic partition, you need to set up the vSphere Management Assistant (vMA) to collect diagnostic information from your host and store it for analysis.

If your ESXi host experiences serious problems, it creates a file with diagnostic information that can be later analyzed to determine the cause of the problems.

You set up your ESXi host to act as a net dump client that transfers the diagnostic file over the network. vMA acts as the net dump server that collects the diagnostic information and saves it to /var/core on the server.

When you set up the net dump environment, follow these guidelines:

Do not install vMA on the same physical host where you set up the net dump client.

If you have multiple ESXi hosts that require the net dump configuration, configure each host separately. One vMA instance is sufficient for collecting the core dump files from multiple ESXi hosts.