HDFS-12351. Explicitly describe the minimal number of DataNodes required to support an EC policy in EC document.. Contributed by Hanisha Koneru.
Project: http://git-wip-us.apache.org/repos/asf/hadoop/repo Commit: http://git-wip-us.apache.org/repos/asf/hadoop/commit/b4d11337 Tree: http://git-wip-us.apache.org/repos/asf/hadoop/tree/b4d11337 Diff: http://git-wip-us.apache.org/repos/asf/hadoop/diff/b4d11337 Branch: refs/heads/YARN-1011 Commit: b4d11337c9271f29dd403d2393812f2ab6f35b35 Parents: dfe0cd8 Author: Arpit Agarwal <a...@apache.org> Authored: Tue Jan 2 12:54:40 2018 -0800 Committer: Arpit Agarwal <a...@apache.org> Committed: Tue Jan 2 12:54:40 2018 -0800 ---------------------------------------------------------------------- .../hadoop-hdfs/src/site/markdown/HDFSErasureCoding.md | 4 ++++ 1 file changed, 4 insertions(+) ---------------------------------------------------------------------- http://git-wip-us.apache.org/repos/asf/hadoop/blob/b4d11337/hadoop-hdfs-project/hadoop-hdfs/src/site/markdown/HDFSErasureCoding.md ---------------------------------------------------------------------- diff --git a/hadoop-hdfs-project/hadoop-hdfs/src/site/markdown/HDFSErasureCoding.md b/hadoop-hdfs-project/hadoop-hdfs/src/site/markdown/HDFSErasureCoding.md index 4459c94..60fd3ab 100644 --- a/hadoop-hdfs-project/hadoop-hdfs/src/site/markdown/HDFSErasureCoding.md +++ b/hadoop-hdfs-project/hadoop-hdfs/src/site/markdown/HDFSErasureCoding.md @@ -99,6 +99,10 @@ Deployment Encoding and decoding work consumes additional CPU on both HDFS clients and DataNodes. + Erasure coding requires a minimum of as many DataNodes in the cluster as + the configured EC stripe width. For EC policy RS (6,3), this means + a minimum of 9 DataNodes. + Erasure coded files are also spread across racks for rack fault-tolerance. This means that when reading and writing striped files, most operations are off-rack. Network bisection bandwidth is thus very important. --------------------------------------------------------------------- To unsubscribe, e-mail: common-commits-unsubscr...@hadoop.apache.org For additional commands, e-mail: common-commits-h...@hadoop.apache.org
