Redundancy Does Not Imply Fault Tolerance
Aishwarya Ganesan, Ramnatthan Alagappan, Andrea Carol Arpaci-Dusseau, Remzi H. Arpaci-Dusseau · ACM Transactions on Storage · 2017
We analyze how modern distributed storage systems behave in the presence of file-system faults such as data corruption and read and write errors. We characterize eight popular distributed storage systems and uncover numerous problems related to file-system fault tolerance. We find that modern distributed systems do not consistently use redundancy to recover from file-system faults: a single file-system fault can cause catastrophic outcomes such as data loss, corruption, and unavailability. We also find that the above outcomes arise due to fundamental problems in file-system fault handling that are common across many systems. Our results have implications for the design of next-generation fault-tolerant distributed and cloud storage systems.