Log rotation and logging options for vmware.log

Products

• VMware vSphere ESXi

Issue/Introduction

This article describes the configurable options that are available for a virtual machine vmware.log file.

This log file records information specific to a running instance of a virtual machine, such as startup configuration, operations, and shutdown of the virtual machine.

Environment

VMware vSphere ESXi 7.x

VMware vSphere ESXi 8.x

Resolution

There are four options you can use to change virtual machine logging and log rotation behaviors:

• The logging setting
• The log.rotateSize setting
• The log.keepOld setting
• The log.fileName setting

Notes:

• To change these settings, you must manually edit the .vmx file located in the VMFS datastore. 
• Some of these parameters are not pre-populated within a virtual machine's configuration file. You may create them where required.
• Occasionally, the virtual machine may stop logging to the vmware.log file and the message <<< Log Throttled >>> can be seen in the vmware.log file. 
• For information on vSphere 7.x and 8.x, see to the 'Manage the Amount of Virtual Machine Log Data' and 'Control When to Switch to New Virtual Machine Log Files' section in the vSphere Monitoring and Performance Guide.

The logging setting

The logging setting allows you to turn logging on or off.

• To turn logging to off, enter logging=false in the virtual machines .vmx file.
• To turn logging back on, change logging=false to logging=true.

The log.rotateSize setting

By default, the virtual machine log file vmware.log is rotated as a result of the virtual machine's Power On or Power Off operation.

To configure log rotation based on file size, include this option in the virtual machines .vmx file:

log.rotateSize = maximum size in bytes the file can grow to

This example specifies the vmware.log file to be rotated when its size reaches 182 kilobytes:

log.rotateSize = 186368

Note: log.rotateSize is not available for vmx use in certain versions of ESXi 5.1 and 5.5. Adding this option in the virtual machine configuration file (.vmx) file does not have any effect. 

The log.keepOld setting

By default, ESX and ESXi from 3.0 through 7.0 keep 6 rotations of the vmware.log file vmware.log, vmware-1.log, vmware-2.log, ... etc.  (8.0 or later version this has been changed to keep 10 rotations.)

To change the level of rotation, use the log.keepOld option in the virtual machines .vmx file.

This example specifies the level of rotation to be 10:

log.keepOld = 10

The log.fileName setting

To specify an alternative location or filename for virtual machine logging, use the log.fileName option in the virtual machines .vmx file.

This example specifies myVMlog as the new file for logs instead of the default vmware.log:

log.fileName = myVMlog

This example directs logs to be written to an alternate directory called myVM in a different VMFS volume, vol1:

log.fileName = /vmfs/volumes/vol1/myVM/myVM.log