We propose a new live-migration paradigm for virtual machines called zero-copy migration. By making the working set of the virtual machine available on the destination host through transparently byte-addressable disaggregated memory, we remove the need for a pre-copy phase while simultaneously reducing the performance impact of the post-copy phase. We describe an open-source implementation of the proposed paradigm based on QEMU-KVM and libvirt, and we evaluate the efficiency of the approach with a deployment on a functional hardware prototype of a memory disaggregation system realized using ThymesisFlow. Using a series of configurable benchmarks, we show that the lead time and blackout time of the migration are equal to best-case scenarios of traditional pre-copy, post-copy and hybrid approaches. Key performance metrics from the perspective of applications running in the virtual machine, such as memory latency and throughput, are improved by up to three orders of magnitude, increasing both flexibility and responsiveness of live-migrations in the datacenter.
@InProceedings{grapentin_et_al:OASIcs.PARMA-DITAM.2024.3, author = {Grapentin, Andreas and Eberhardt, Felix and Zagorni, Tobias and Polze, Andreas and Gazzetti, Michele and Pinto, Christian}, title = {{Zero-Copy, Minimal-Blackout Virtual Machine Migrations Using Disaggregated Shared Memory}}, booktitle = {15th Workshop on Parallel Programming and Run-Time Management Techniques for Many-Core Architectures and 13th Workshop on Design Tools and Architectures for Multicore Embedded Computing Platforms (PARMA-DITAM 2024)}, pages = {3:1--3:13}, series = {Open Access Series in Informatics (OASIcs)}, ISBN = {978-3-95977-307-2}, ISSN = {2190-6807}, year = {2024}, volume = {116}, editor = {Bispo, Jo\~{a}o and Xydis, Sotirios and Curzel, Serena and Sousa, Lu{\'\i}s Miguel}, publisher = {Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik}, address = {Dagstuhl, Germany}, URL = {https://drops.dagstuhl.de/entities/document/10.4230/OASIcs.PARMA-DITAM.2024.3}, URN = {urn:nbn:de:0030-drops-196972}, doi = {10.4230/OASIcs.PARMA-DITAM.2024.3}, annote = {Keywords: disaggregation, disaggregated memory, vm live migration, thymesisflow, power9, opencapi, performance evaluation, zero copy} }
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