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Posted to common-commits@hadoop.apache.org by zj...@apache.org on 2015/05/22 23:42:06 UTC
[48/50] [abbrv] hadoop git commit: HDFS-4383. Document the lease
limits. Contributed by Arshad Mohammad.
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 <aa...@apache.org>
Authored: Thu May 21 17:30:43 2015 +0900
Committer: Zhijie Shen <zj...@apache.org>
Committed: Fri May 22 12:42:58 2015 -0700
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hadoop-hdfs-project/hadoop-hdfs/CHANGES.txt | 2 ++
.../hdfs/server/common/HdfsServerConstants.java | 23 +++++++++++++++++---
2 files changed, 22 insertions(+), 3 deletions(-)
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http://git-wip-us.apache.org/repos/asf/hadoop/blob/e6cc8c4d/hadoop-hdfs-project/hadoop-hdfs/CHANGES.txt
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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
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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.