I/O Performance Improvement with Striping File Layout Considering Storage of Intermediate Data

Fully Homomorphic Encryption (FHE) is encryption with which a user can execute calculations using its encrypted data without decrypting it. Many users hesitate to upload their private data to a public cloud computing system even though the user desire to utilize the great computing power of the public cloud computing system. FHE address this issue. A user can perform the user's calculation by the cloud computing system's processing power without providing its plain data. In the case of FHE data mining based on the Apriori algorithm, the program alternately access files. In this case, the program has to access files involving long-distance seek on a usual file layout. In a previous paper, a method for improving the I/O performance of accessing multiple large files based on striping file layout. However, this method does not support placing new intermediate files near the data files during a program without involving seeking long-distance seek between data files and newly created intermediate files. In this paper, we propose a method for improving this file layout by reserving areas for intermediate files. We then evaluate the proposed method and show that the proposed method can reduce I/O time.