Under the Hood: Hadoop Distributed Filesystem reliability with Namenode and Avatarnode (Facebook Engineering)

From an overview of big data at Facebook

"The Hadoop Distributed Filesystem (HDFS) forms the basis of many large-scale storage systems at Facebook and throughout the world. Our Hadoop clusters include the largest single HDFS cluster that we know of, with more than 100 PB physical disk space in a single HDFS filesystem. Optimizing HDFS is crucial to ensuring that our systems stay efficient and reliable for users and applications on Facebook."

Under the Hood: Hadoop Distributed Filesystem reliability with Namenode and Avatarnode