How to Check VMkernel Logs for More Troubleshooting

The VMkernel log file (vmkernel.log) is one of the most critical logs in VMware ESXi, as it records low-level system operations and events related to the VMkernel, such as hardware interaction, storage and network events, virtual machine scheduling, device driver information and ESXi host errors and warnings. So we need to find out the location of VMkernel log files for more details, following are the way to find VMkernel log file.

Where to Find VMkernel Log File

VMkernel log file include three types, each one having a different purpose. Following are the introductions to these log files.

→ VMkernel

You can find this log file on ESXi host in this location: /var/log/vmkernel.log. This log file records all activities that related to virtual machines (VMs) and ESXi. These activities include device events, storage and networking, which provide a diagnostic method for hardware-related issues.

→ VMkernel Summary

The location of the VMkernel summary is /var/log/vmksummary.log, which offers a snapshot of the ESXi host's operational state, covering startup and shutdown activities, system resource utilization, and key performance metrics.

→ VMkernel Warnings

The location of the VMkernel warnings is /var/log/vmwarning.log. This log file includes warning messages produced by the VMkernel, the core of the ESXi hypervisor. It captures events and conditions that may need attention but do not indicate critical errors.

How to Check VMkernel Log File [2 Methods]

In order to monitor and troubleshoot key operations and events related to the core functions of the ESXi hypervisor, we need to access VMkernel log file. Here are two methods of accessing VMkernel log file.

Method 1. Access VMkernel Log File via SSH

To see the VMkernel file for more detailes, it's an easy to use SSH by following steps below.

1. You need to enable SSH on the host first. Navigate to Host Manage Service and starting the SSH service in vSphere Web Client.

2. Connect to the ESXi host using the IP address of the ESXi host.

3. Log in with the appropriate root credentials.

4. Navigate to the log directory: cd/var/log

5. Enter the following commands to view the VMkernel log:

To display entire log:

To view recent entries:

To search for specific terms

Method 2. Access VMkernel Log File via ESXi Host Client

It’s an easier way to access VMkernel log file through ESXi host client.

Step 1: Navigate to Monitor, then select Logs from the sidebar.

Step 2: In the list of logs, you can locate and select VMkernel log to view the recent log entries, also you can download or export the logs if needed.

Differences: VMkernel Log File vs. VM Log File

Although VMkernel log file and VM log file are both important for troubleshooting in VMware environments, they are different. Following are their differences in purpose and location.

	VMkernel Log File	VM Log File
Location	/var/log/vmkernel.log	/vmfs/volumes/datastore_name/VM_folder/vmware.log
Purpose	The core of the ESXi hypervisor Diagnose low-level issues	Record events specific to the virtual machine Troubleshoot issues at the VM level

Further Protection: An Effective Way to Protect VMs in VMware

The VMkernel Log file already provides us with a means of diagnosing low-level problems and host-level errors. In a virtual environment, this is not nearly enough security to prevent data loss, so our VMs still need further protection.

Here is a recommendation to AOMEI Cyber Backup, which is a specialized software that provides you with an easy way to protect your virtual machine data. You can enjoy more benefits with AOMEI Cyber Backup.

✍Easy to Use: The intuitive interface allows you to connect, create tasks, and implement protection with just a few clicks. ✍Agentless Backup: You can backup VMs without installing agents. ✍Automated and Schedules Backups: Automatic and scheduled backups, minimizing the risk of data loss and simplifying the backup process. ✍Comprehensive Backup Options: Full, incremental, and differential backups enable users to select the backup strategy that best fits their needs. ✍Backup Archive: Easily store data to Amazon cloud for better storage and long-term data protection.

Click the below button to download AOMEI Cyber Backup for the free version.

3 Easy Steps to Backup VMware ESXi VMs

Step 1. Bind Device

Within the AOMEI Cyber Backup interface, navigate to Source Device and select VMware then click + Add VMware Device. After doing this, enter requires information and click Confirm to bind device.

Step 2. Create New Task

Navigate to Backup Task + Create New Task. Then setup Task Name, Backup Type, Device, Target, Archive and Schedule.

• Target: You can choose to backup to a local path, or to a network path.
• Archive: Add Amazon S3 buckets first and select Archiving backup versions to Amazon S3.
• Schedule: You can select full, differential, or incremental backup.

📢Note: Although the free version is sufficient for most needs, you can upgrade to Premium version to enjoy more features. After the upgrade you can experience: Backup Cleanup, Restore to new location etc.

Step 3. Start Backup

Click Start Backup and select Add the schedule and start backup now, or Add the schedule only.

Conclusion

VMkernel log files are an important tool for monitoring and troubleshooting ESXi host kernel operations. Whether diagnosing hardware failures, tracking system events, or investigating errors, VMkernel logs are critical to effectively managing ESXi hosts and proactively monitoring systems. In addition, we need AOMEI Cyber Backup as a complementary tool for data protection.