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HBASE-4517 Document new replication features in 0.92 

git-svn-id: https://svn.apache.org/repos/asf/hbase/trunk@1177866 13f79535-47bb-0310-9956-ffa450edef68
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Michael Stack 2011-09-30 22:29:09 +00:00
parent c80eaecce1
commit 1e606a3790
1 changed files with 14 additions and 16 deletions
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src/site/xdoc/replication.xml
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@ -74,6 +74,10 @@
and the master cluster will do its “best effort” to balance the stream
of replication on the slave clusters by relying on randomization.
</p>
<p>
As of version 0.92 HBase supports master/master and cyclic replication as
well as replication to multiple slaves.
</p>
<img src="images/replication_overview.png"/>
</section>
<section name="Enabling replication">
@ -104,10 +108,14 @@
<p>
In a separate thread, the edit is read from the log (as part of a batch)
and only the KVs that are replicable are kept (that is, that they are part
of a family scoped GLOBAL in the family's schema and non-catalog so not
.META. or -ROOT-). When the buffer is filled, or the reader hits the
end of the file, the buffer is sent to a random region server on the
slave cluster.
of a family scoped GLOBAL in the family's schema, non-catalog so not
.META. or -ROOT-, and did not originate in the target slave cluster - in
case of cyclic replication).
</p>
<p>
The edit is then tagged with the master's cluster UUID.
When the buffer is filled, or the reader hits the end of the file,
the buffer is sent to a random region server on the slave cluster.
</p>
<p>
Synchronously, the region server that receives the edits reads them
@ -115,6 +123,8 @@
Once all edits are read, each buffer is flushed using the normal HBase
client (HTables managed by a HTablePool). This is done in order to
leverage parallel insertion (MultiPut).
The master's cluster UUID is retained in the edits applied at the
slave cluster in order to allow cyclic replication.
</p>
<p>
Back in the master cluster's region server, the offset for the current
@ -394,18 +404,6 @@
queues of another dead RS, we will miss the data from the queues
that weren't copied.
</li>
<li>
HBASE-2196, a master cluster can only support a single slave, some
refactoring is needed to support this.
</li>
<li>
HBASE-2195, edits are applied disregard their home cluster, it should
carry that data and check it.
</li>
<li>
HBASE-3130, the master cluster needs to be restarted if its region
servers lose their session with a slave cluster.
</li>
</ol>
</section>
</body>