Microarchitectures for Robust and Efficient Incremental Backup in Intermittently-Powered Systems

Defense type
Thesis
Starting date
End date
Location
IRISA Rennes
Room
Salle Métivier
Speaker
Davide PALA - Equipe TARAN
Main department
Theme
Embedded devices powered with environmental energy harvesting, have to sustain computation while experiencing unexpected power failures. To preserve the progress across the power interruptions, Non-Volatile Memories (NVMs) are used to quickly save the state. This dissertation first presents an overview and comparison of different NVM technologies, based on different surveys from the literature. The second contribution we propose is a dedicated backup controller, called Freezer, that implements an on-demand incremental backup scheme.
This can make the size of the backup 87.7% smaller then a full-memory backup strategy from the state of the art (SoA). Our third contribution addresses the problem of corruption of the state, due to interruptions during the backup process. Two algorithms are presented, that improve on the Freezer incremental backup process, making it robust to errors, by always guaranteeing the existence of a correct state, that can be restored in case of backup errors. These two algorithms can consume 23% less energy than the usual double-buffering technique used in the SoA. The fourth contribution, addresses the scalability of our proposed approach. Combining Freezer with Bloom filters, we introduce a backup scheme that can cover much larger address spaces, while achieving a backup size which is half the size of the regular Freezer approach.
 
Composition of the jury
Abdoulaye Gamatié, Directeur de Recherche, CNRS, LIRMM, Montpellier (rapporteur)
Tanguy Risset, Professeur, INSA Lyon, CITI (rapporteur)
Maria Méndez Real, Maitre de Conférences, Polytech Université de Nantes, IETR
Daniel Etiemble, Professeur, Université Paris-Saclay, LRI
Erven Rohou, Directeur de Recherche, Inria, IRISA, Rennes (invité)
Olivier Sentieys, Professeur, Université de Rennes, Inria, IRISA (directeur de thèse)
Ivan Miro-Panades, Ingénieur-Chercheur, CEA-List, Grenoble (co-directeur de thèse)