HDFS.7849. Update documentation for enabling a new feature in rolling upgrade ( Contributed by J.Andreina )

(cherry picked from commit 5be5129d93)
This commit is contained in:
Vinayakumar B 2015-03-19 19:05:42 +05:30
parent ceb39c1cc6
commit 786ba9784d
2 changed files with 12 additions and 0 deletions

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@ -459,6 +459,9 @@ Release 2.7.0 - UNRELEASED
HDFS-7054. Make DFSOutputStream tracing more fine-grained (cmccabe)
HDFS.7849. Update documentation for enabling a new feature in rolling
upgrade ( J.Andreina via vinayakumarb )
OPTIMIZATIONS
HDFS-7454. Reduce memory footprint for AclEntries in NameNode.

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@ -47,6 +47,15 @@
These two capabilities make it feasible to upgrade HDFS without incurring HDFS downtime.
In order to upgrade a HDFS cluster without downtime, the cluster must be setup with HA.
</p>
<p>
If there is any new feature which is enabled in new software release, may not work with old software release after upgrade.
In such cases upgrade should be done by following steps.
</p>
<ol>
<li>Disable new feature.</li>
<li>Upgrade the cluster.</li>
<li>Enable the new feature.</li>
</ol>
<p>
Note that rolling upgrade is supported only from Hadoop-2.4.0 onwards.
</p>