hadoop-common-commits mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From Apache Wiki <wikidi...@apache.org>
Subject [Hadoop Wiki] Trivial Update of "Hbase/MultipleMasters" by LarsFrancke
Date Tue, 03 Nov 2009 01:00:20 GMT
Dear Wiki user,

You have subscribed to a wiki page or wiki category on "Hadoop Wiki" for change notification.

The "Hbase/MultipleMasters" page has been changed by LarsFrancke.
The comment on this change is: typos, small corrections.
http://wiki.apache.org/hadoop/Hbase/MultipleMasters?action=diff&rev1=4&rev2=5

--------------------------------------------------

  '''This document is still a draft'''
  
- Since version 0.20.0 (not released at this moment) HBase supports multiple Masters to provide
higher availability. It works in the same way that Bigtable does as explained in the 2006
paper. This page contains the information you need to set it up, maintain it, and to understand
how it works under the hood.
+ Since version 0.20.0 HBase supports multiple Masters to provide higher availability. It
works in the same way that Bigtable does as explained in the 2006 paper. This page contains
the information you need to set it up, maintain it, and to understand how it works under the
hood.
  
  == Single Master Setup ==
  
- The [[http://hadoop.apache.org/hbase/docs/current/api/overview-summary.html#overview_description|Getting
Started]] documentation describes set up with a single Master. A cluster can run without a
Master for a number of few minutes but your regions will be unable to split. If it does happen,
you can go to any other machine with the correct installation/configuration and do {{{$ ${HBASE_HOME}/bin/hbase-daemon.sh
start master}}}.  This newly started Master will take over Master functions.
+ The [[http://hadoop.apache.org/hbase/docs/current/api/overview-summary.html#overview_description|Getting
Started]] documentation describes set up with a single Master. A cluster can run without a
Master for a few minutes but your regions will be unable to split. If it does happen, you
can go to any other machine with the correct installation/configuration and do {{{$ ${HBASE_HOME}/bin/hbase-daemon.sh
start master}}}. This newly started Master will take over Master functions.
  
- Currently the Hadoop Distributed Filesystem is '''not''' highly available so if the Namenode
resides on the same machine is your Master, the cluster is still wedged and you will have
to shut down HBase with a high probability of losing data.
+ Currently the Hadoop Distributed Filesystem is '''not''' highly available so if the Namenode
resides on the same machine as your Master, the cluster is still wedged and you will have
to shut down HBase with a high probability of losing data.
  
  == Multiple Masters Setup ==
  
@@ -16, +16 @@

  
  === Basic knowledge ===
  
- The multi-master feature introduced in 0.20 does not add cooperating Masters; there is still
just one working Master while the other ''backups'' wait. For example, if you start 200 Masters
only 1 will be active while the others wait for it to die. The switch usually takes zookeeper.session.timeout
plus a couple of seconds to occur. See "How it works inside" below for more information.
+ The multi-master feature introduced in 0.20.0 does not add cooperating Masters; there is
still just one working Master while the other ''backups'' wait. For example, if you start
200 Masters only 1 will be active while the others wait for it to die. The switch usually
takes `zookeeper.session.timeout` plus a couple of seconds to occur. See "How it works inside"
below for more information.
  
  === Designing your highly available setup ===
  

Mime
View raw message