A Large-Scale Study of Failures on Petascale Supercomputers

With the rapid development of supercomputers, the scale and complexity are ever increasing, and the reliability and resilience are faced with larger challenges. There are many important technologies in fault tolerance, such as proacrive failure avoidance technologies based on fault prediction, reactive fault tolerance based on checkpoint, and scheduling technologies to improve reliability. Both qualitative and quantitative descriptions on characteristics of system faults are very critical for these technologies, This study analyzes the source of failures on two typical petascale supercomputers called Sunway BlueLight （based on multi-core CPUs） and Sunway TaihuLight （based on heterogeneous manycore CPUs）. It uncovers some interesting fault characteristics and finds unknown correlation relationship among main components＇ faults. Finally the paper analyzes the failure time of the two supercomputers in various grains of resource and different time spans, and builds a uniform multi-dimensional failure time model for petascale supereomputers.

Isotopic Composition of Atmospheric Precipitation in the Cis-Ural Region

Using the Global Network of Isotopes in Precipitation(GNIP)method at three stations in the Cis-Ural region(Iskor,Perm,and Kungur),the monitoring results of the isotope composition of atmospheric precipitation conducted in 2016-2019 are reported.Local lines of meteoric waters were obtained for each station and for the Cis-Ural region as a whole.The latitudinal zoning of changes in isotope parameters from north to south in the Cis-Ural region is noted,which is related to meteorological parameters.The northern regions are characterized by isotopically light values compared to the southern regions.Additionally,the correlation relationship between the isotopic compositions of atmospheric precipitation and meteorological parameters at each station is estimated.Correlation analysis data show that about 50%-90%of variations in the isotopic composition of precipitation within the annual cycle are determined by the air temperature.At the same time,the amount of precipitation shows a relationship between the average strength and the isotopic composition of precipitation for a series of observations at Kungur Station;for a series of observations at Iskor and Perm stations,there is no correlation.Differences in the relationship with meteorological data are explained by different sources of moisture introduction to the station and,accordingly,the formation of the isotopic composition of precipitation.The flow of moisture is controlled by the transfer of air masses in different directions,the formation of cyclones and anticyclones.So,for the northern part of the region during the year is characterized by the predominance of cyclones,whereas for the southern-anticyclones.