guodongdong created HDFS-6154:
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Summary: Improve the speed of saveNameSpace，making HDFS restart
and checkPoint faster
Key: HDFS-6154
URL: https://issues.apache.org/jira/browse/HDFS-6154
Project: Hadoop HDFS
Issue Type: Improvement
Affects Versions: 2.3.0
Reporter: guodongdong
There are two stage In namenode savenamespace, serializing INode, calculate
MD5 and write to disk. Now, two stage is doing serially, In this improvement,
it is doing parallel, one thread do serializing INode, other thread do
calculating MD5 and writing to disk, it double speed of savenamespace, Detail
is show in table:
Testing environment:
only test namenode savenamespace, dfsadmin -saveNamespace
machine: 144GB, Intel(R) Xeon(R) CPU E5645 @ 2.40GHz, 12 cpu, Raid 5 SAS
Disk, jdk 1.7.0
||image size||before optimizing||after optimizing ||
|1.2GB|22sec|11sec|
|4.3GB|66sec|36sec|
|22GB|406sec|250sec|
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