The Hortonworks Blog

More from Nicholas Sze

This blog is a follow up on our previous blog “Snapshots for HDFS

In June we had posted an early prototype of snapshots that allowed us to experiment with a few ideas in HDFS-2802. Since then we have added more details to the design document and made significant progress on a brand new implementation (over 40 subtasks in HDFS-2802).

Some of the highlights of this new design include:

  • Read-Only Copy-on-Write (COW) snapshots (but can be extended RW later)
  • Snapshots for entire namespace or sub directories
  • Snapshots are managed by Admin, but users are allowed to take snapshots
  • Snapshots are efficient
  • Creation is instantaneous with O(1) cost.

Motivation

Apache Hadoop provides a high performance native protocol for accessing HDFS. While this is great for Hadoop applications running inside a Hadoop cluster, users often want to connect to HDFS from the outside. For examples, some applications have to load data in and out of the cluster, or to interact with the data stored in HDFS from the outside. Of course they can do this using the native HDFS protocol but that means installing Hadoop and a Java binding with those applications.…

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