Installation guide

Log files
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request_irq
Number of guest interrupt window request exits.
signal_exits
Number of guest exits due to pending signals from the host.
tlb_flush
Number of tlb_flush operations performed by the hypervisor.
Note
The output information from the kvm_stat command is exported by the KVM hypervisor as
pseudo files located in the /sys/kernel/debug/kvm/ directory.
34.3. Log files
KVM uses various log files. All the log files are standard ASCII files, and accessible with a text editor.
• The default directory for all file-based images is the /var/lib/libvirt/images directory.
• qemu-kvm.[PID].log is the log file created by the qemu-kvm process for each fully virtualized
guest. When using this log file, you must retrieve the given qemu-kvm process PID, by using the ps
command to examine process arguments to isolate the qemu-kvm process on the virtual machine.
Note that you must replace the [PID] symbol with the actual PID qemu-kvm process.
If you encounter any errors with the Virtual Machine Manager, you can review the generated data in
the virt-manager.log file that resides in the /.virt-manager directory. Note that every time
you start the Virtual Machine Manager, it overwrites the existing log file contents. Make sure to backup
the virt-manager.log file, before you restart the Virtual Machine manager after a system error.
34.4. Troubleshooting with serial consoles
Linux kernels can output information to serial ports. This is useful for debugging kernel panics and
hardware issues with video devices or headless servers. The subsections in this section cover setting
up serial console output for machines running Red Hat Enterprise Linux 6 virtualization kernels and
their virtualized guests.
This section covers how to enable serial console output for fully virtualized guests.
Fully virtualized guest serial console output can be viewed with the virsh console command.
Be aware fully virtualized guest serial consoles have some limitations. Present limitations include:
• output data may be dropped or scrambled.
The serial port is called ttyS0 on Linux or COM1 on Windows.
You must configure the virtualized operating system to output information to the virtual serial port.
To output kernel information from a fully virtualized Linux guest into the domain modify the /boot/
grub/grub.conf file by inserting the line console=tty0 console=ttyS0,115200.
title Red Hat Enterprise Linux Server (2.6.32-36.x86-64)
root (hd0,0)
kernel /vmlinuz-2.6.32-36.x86-64 ro root=/dev/volgroup00/logvol00
console=tty0 console=ttyS0,115200