Presented by : Ran Koretzki

Basic Introduction What are VM’s ? What is migration ? What is Live migration ?

What are VM’s ? VM’s (Virtual Machines) - "completely isolated guest operating system installation within a normal host operating system". Modern virtual machines are implemented with either software emulation or hardware virtualization or (in most cases) both together.software emulationhardware virtualization This allows to run multiple independent VM’s on a single physical Machine. VM’s operating systems are not hardware depended.

What are VM’s ? Traditional ArchitectureVirtual Architecture

Benefits What are VM’s ? Hardware independence. Encapsulation - VMs can be described in a file Possible to ‘snapshot’. Easy to move and to backup. Easy to clone and scale wide a server application. Many VM venders : VMware, Microsoft, Citrix… Enables running multiple operating systems Consolidation & use of unused computation power. Resource management. High availability & disaster recovery. Easy Management. Migration – next on the agenda.

Migration Definition - The ability to move VM’s from one PH to another. In the past, to move a VM between 2 PH, it was necessary to shutdown the VM, allocate the needed recourses to the new PH, move the VM files, and start the VM in the new host. The recourses that need to be transferred are : memory, the internal state of the devices and of the virtual CPU. The must time consuming to transfer is memory. The problem : downtime. The solution was at first Automation, but the real improvement came with Live Migration.

Live Migration Wiki Definition - allows a server administrator to move a running virtual machine or application between different physical machines without disconnecting the client or application. For a successful live migration, the memory, storage, and network connectivity of the virtual machine needs to be migrated to the destination. It mean it allows the server admin to move VM’s between PH transparently to the clients. It is done usually for Load balance between PH and for migration in case of a hardware failure. Live migration of virtual machines Zero downtime

Presented by : Ran Koretzki By: Fabio Checconi, Tommaso Cucinotta, Manuel Stein.

1.Show a heuristic to reduce the downtime of a VM during live migration by scheduling which memory pages to transmit first.

Computational Resources: Scheduling Guarantee by the Kernel – (Q, P). Meaning period P and share Q Network Resources: b needs to be constant and Possible to reserve. An unstable network is not part of this model, but a migration will still succeed (but it may not be Live Migration)

The authors have modified the KVM hypervisor. Page Tracing mechanism Page accessed are traced within the hypervisor, using a bitmap The implementation will exploit this information to modify transfer order Simulations – Virtualized VideoLAN Client (VLC) as a streaming server 6500 mapped pages (16KB/page) Transfer rate of 100MBit/sec. 8 sec. (!)

Guaranteed bandwidth of 50 Mbit/s Standard vs. LRU 570 -> 300 (47%) (K=1) 360 -> 290 (19.4%) (K=3) > 4500 (6.25%) (K=1) > 5000 (9.1%) (K=3)

It’s possible to minimize downtime and improve QoS with simple page ordering algorithms With a certain bandwidth, LRU has been proved as an effective aid for page ordering, achieving good results. Further Work needs to be done…