Byzantine Anomaly Testing for Charm++: Providing Fault Tolerance and Survivability for Charm++ Empowered Clusters

Recently shifts in high-performance computing have increased the use of clusters built around cheap commodity processors. A typical cluster consists of individual nodes, containing one or several processors, connected together with a highbandwidth, low-latency interconnect. There are many benefits to using clusters for computation, but also some drawbacks, including a tendency to exhibit low Mean Time To Failure (MTTF) due to the sheer number of components involved. Recently, a number of fault-tolerance techniques have been proposed and developed to mitigate the inherent unreliability of clusters. These techniques, however, fail to address the issue of detecting non-obvious faults, particularly Byzantine faults. At present, effectively detecting Byzantine faults is an open problem. We describe the operation of ByzwATCh, a module for run-time detecting Byzantine hardware errors as part of the Charm++ parallel programming framework

Studying the small-scale structure of a polarization jet during the April 20, 2018 geomagnetic storm

In this work, we study the small-scale structure of a polarization jet in the subauroral region during the April 20, 2018 geomagnetic storm. We report measurement results of plasma parameters inside the polarization jet with a maximum sampling rate of up to 1 kHz, obtained with Langmuir probes installed on the NorSat-1 microsatellite. The study establishes the presence of temperature and electron density inhomogeneities inside the polarization jet with spatial dimensions of tens to hundreds of meters. The previously known features of the polarization jet evolution have been confirmed. We have also found that the distribution of the electron temperature inside the jet forms two separate peaks as the geomagnetic activity develops during the storm

Cluster Security Research Challenges

In this paper, we share insights from our group experience building and experimenting on high performance computing clusters to support our research developing novel cluster security protection techniques and tools

In situ observations of ionospheric heating effects: First results from a joint SURA and NorSat-1 experiment

This work presents the first results of measurements of artificial plasma disturbance characteristics using the low‐orbit NorSat‐1 satellite, which are excited when the ionospheric F2 layer is modified by powerful high‐frequency (HF) waves emitted by the SURA heating facility. NorSat‐1 carries the multineedle Langmuir probe instrument, which is capable of sampling the electron density at a nominal rate up to 1 kHz. The uniqueness of this experiment lies in the fact that the satellite passes very close to the center of the HF‐perturbed magnetic flux tube and in situ observations are first carried out in winter when the absorption is still small in the morning as the Sun is low above the horizon. There are HF‐induced plasma temperature and density variations at satellite altitudes of about 580 km. Plasma irregularities are detected by in situ measurements down to 200 m at the southern border of the SURA heating region