The Quantcast File System

摘要

The Quantcast File System (QFS) is an efficient alternative to the Hadoop Distributed File System (HDFS). QFS is written in C++, is plugin compatible with Hadoop MapRe-duce, and offers several efficiency improvements relative to HDFS: 50% disk space savings through erasure coding instead of replication, a resulting doubling of write throughput, a faster name node, support for faster sorting and logging through a concurrent append feature, a native command line client much faster than hadoop fs, and global feedback-directed I/O device management. As QFS works out of the box with Hadoop, migrating data from HDFS to QFS involves simply executing hadoop distcp.