HDFS-4383. Document the lease limits. Contributed by Arshad Mohammad.
Project: http://git-wip-us.apache.org/repos/asf/hadoop/repo Commit: http://git-wip-us.apache.org/repos/asf/hadoop/commit/e6cc8c4d Tree: http://git-wip-us.apache.org/repos/asf/hadoop/tree/e6cc8c4d Diff: http://git-wip-us.apache.org/repos/asf/hadoop/diff/e6cc8c4d Branch: refs/heads/YARN-2928 Commit: e6cc8c4d1285029d52d7234f06cf3b13fa83abb7 Parents: af9c559 Author: Akira Ajisaka <[email protected]> Authored: Thu May 21 17:30:43 2015 +0900 Committer: Zhijie Shen <[email protected]> Committed: Fri May 22 12:42:58 2015 -0700 ---------------------------------------------------------------------- hadoop-hdfs-project/hadoop-hdfs/CHANGES.txt | 2 ++ .../hdfs/server/common/HdfsServerConstants.java | 23 +++++++++++++++++--- 2 files changed, 22 insertions(+), 3 deletions(-) ---------------------------------------------------------------------- http://git-wip-us.apache.org/repos/asf/hadoop/blob/e6cc8c4d/hadoop-hdfs-project/hadoop-hdfs/CHANGES.txt ---------------------------------------------------------------------- diff --git a/hadoop-hdfs-project/hadoop-hdfs/CHANGES.txt b/hadoop-hdfs-project/hadoop-hdfs/CHANGES.txt index 5bcaddd..77d7369 100644 --- a/hadoop-hdfs-project/hadoop-hdfs/CHANGES.txt +++ b/hadoop-hdfs-project/hadoop-hdfs/CHANGES.txt @@ -575,6 +575,8 @@ Release 2.8.0 - UNRELEASED HDFS-4185. Add a metric for number of active leases (Rakesh R via raviprak) + HDFS-4383. Document the lease limits. (Arshad Mohammad via aajisaka) + OPTIMIZATIONS HDFS-8026. Trace FSOutputSummer#writeChecksumChunks rather than http://git-wip-us.apache.org/repos/asf/hadoop/blob/e6cc8c4d/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/common/HdfsServerConstants.java ---------------------------------------------------------------------- diff --git a/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/common/HdfsServerConstants.java b/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/common/HdfsServerConstants.java index c664b01..26a7ab3 100644 --- a/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/common/HdfsServerConstants.java +++ b/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/common/HdfsServerConstants.java @@ -42,10 +42,27 @@ import org.apache.hadoop.util.StringUtils; @InterfaceAudience.Private public interface HdfsServerConstants { int MIN_BLOCKS_FOR_WRITE = 1; - // - // Timeouts, constants - // + /** + * For a HDFS client to write to a file, a lease is granted; During the lease + * period, no other client can write to the file. The writing client can + * periodically renew the lease. When the file is closed, the lease is + * revoked. The lease duration is bound by this soft limit and a + * {@link HdfsServerConstants#LEASE_HARDLIMIT_PERIOD hard limit}. Until the + * soft limit expires, the writer has sole write access to the file. If the + * soft limit expires and the client fails to close the file or renew the + * lease, another client can preempt the lease. + */ long LEASE_SOFTLIMIT_PERIOD = 60 * 1000; + /** + * For a HDFS client to write to a file, a lease is granted; During the lease + * period, no other client can write to the file. The writing client can + * periodically renew the lease. When the file is closed, the lease is + * revoked. The lease duration is bound by a + * {@link HdfsServerConstants#LEASE_SOFTLIMIT_PERIOD soft limit} and this hard + * limit. If after the hard limit expires and the client has failed to renew + * the lease, HDFS assumes that the client has quit and will automatically + * close the file on behalf of the writer, and recover the lease. + */ long LEASE_HARDLIMIT_PERIOD = 60 * LEASE_SOFTLIMIT_PERIOD; long LEASE_RECOVER_PERIOD = 10 * 1000; // in ms // We need to limit the length and depth of a path in the filesystem.
