While troubleshooting the backup or restore of a virtual machine it may be necessary to get more information on what is actually happening on the ESX server. The main log used for troubleshooting is the hostd.log but other logs are available here as well.
Note: The hostd.log is a rolling log. It should be saved out shortly after reproducing the issue.
In the VI Client navigate to Administration - Export System Logs (Figure 1).
Select the ESX(i) host(s) to export the logs from and the destination then click OK. (Figure 2)