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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 and the master cluster will do its “best effort” to balance the stream
of replication on the slave clusters by relying on randomization. of replication on the slave clusters by relying on randomization.
</p> </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"/> <img src="images/replication_overview.png"/>
</section> </section>
<section name="Enabling replication"> <section name="Enabling replication">
@ -104,10 +108,14 @@
<p> <p>
In a separate thread, the edit is read from the log (as part of a batch) 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 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 of a family scoped GLOBAL in the family's schema, non-catalog so not
.META. or -ROOT-). When the buffer is filled, or the reader hits the .META. or -ROOT-, and did not originate in the target slave cluster - in
end of the file, the buffer is sent to a random region server on the case of cyclic replication).
slave cluster. </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>
<p> <p>
Synchronously, the region server that receives the edits reads them 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 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 client (HTables managed by a HTablePool). This is done in order to
leverage parallel insertion (MultiPut). 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>
<p> <p>
Back in the master cluster's region server, the offset for the current 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 queues of another dead RS, we will miss the data from the queues
that weren't copied. that weren't copied.
</li> </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> </ol>
</section> </section>
</body> </body>