All ESXi hosts run a syslog service (vmsyslogd), which logs messages from the VMkernel and other system components to log files. You can use the vSphere Client or the esxcli system syslog vCLI command to configure the syslog service.
1. In the vSphere Client inventory, select the host.
2. Click the Configuration tab.
3. In the Software panel, click Advanced Settings.
4. Select Syslog in the tree control.
5. To set up logging globally, click global and make changes to the fields on the right.
6. (Optional) To overwrite the default log size and log rotation for any of the logs.
a. Click loggers.
b. Click the name of the log you that want to customize and enter the number of rotations and log size you want.
7. Click OK. Changes to the syslog options take effect immediately.