Virtualization software Qemu 2.5: 3D in Linux VMs and better live migration – Heise Newsticker

Two extensions transferring VMs running on a different system – RSPEAK_START. About new section Ellen Linux will in future be able to use 3D acceleration of the graphics hardware in the host in KVM VMs.

The new version 2.5 of the virtualization software Qemu brings two features that transfer a a running virtual machine (VM) to another host system to make it more robust. In such a live migration of memory contents of the VM is typically advance transferred to the new host; then the VM is stopped to transfer the Date Migration beginning altered memory contents and other status information to the host where the VM is then restarted.

In the new with Qemu 2.5 “post-copy live migration “the memory contents in the live migration on the old host remains and is called up as required by the new host. This retrospective requesting happens either when you first access a memory area or at a later date to complete the live migration.

Temporary performance hit

This degrades the VM -Performance until the entire memory has been transferred from the old to the new host. For this, however, the approach enables live migration in situations where the VM memory uses very strong: When previously used approach may in already tight network bandwidth happen that a live migration is not practical because the VM to be stopped for too long would have to transfer the Date Migration beginning altered memory contents.

This new approach of Qemu used in virtualization with KVM or Xen, however, requires a kernel with the Userfaultfd function that Linux 4.3 mastered. The second new Qemu function also works with older versions of the kernel: When “Autoconverge Live Migration” Qemu reduces usable in the VM processor time when live migration is initiated; as a result, often also decreases the amount of changes in the working memory what makes Live Migration practicable.

OpenGL acceleration in VMs

The new version of Qemu also brings interfaces, use with a Linux in a powered with KVM VM 3D acceleration of the host can. This “Virgl 3D” mentioned method requires drivers that the expected in January Linux kernel 4.4 and the recently released Mesa 11.1 included.

Qemu 2.5 also brings hotplug support for PCIe devices, the number of virtual functions provide. In Kombiantion with Linux 4.4 driver virtio PCI is designed to provide better performance. Details on these and other innovations to illustrate the announcement of qemu 2.5 and the detailed changelog. (THL)