1VOTEQUORUM_OVERVIEWC(o8r)osync Cluster Engine Programmer's MaVnOuTaElQUORUM_OVERVIEW(8)
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NAME

6       votequorum_overview - Votequorum Library Overview
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OVERVIEW

9       The  votequuorum  library is delivered with the corosync project. It is
10       the external interface to the vote-based quorum service.  This  service
11       is  optionally  loaded  into  all  ndes  in a corosync cluster to avoid
12       split-brain situations. It does  this  by  having  a  number  of  votes
13       assigned  to  each  system in the cluster and ensuring that only when a
14       majority of the votes are present, cluster operations  are  allowed  to
15       proceed.
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17       The library provides a mechanism to:
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19       * Query the quorum status
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21       * Get a list of nodes known to the quorum service
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23       * Receive notifications of quorum state changes
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25       * Change the number of votes assigned to a node
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27       * Change the number of expected votes for a cluster to be quorate
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29       * Connect an additional quorum device to allow small clusters to remain
30       quorate during node outages.
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32       votequorum reads its configuration from the objdb. The  following  keys
33       are read when it starts up:
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35       * quorum.expected_votes
36       * quorum.votes
37       * quorum.quorumdev_poll
38       * quorum.disallowed
39       * quorum.two_node
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41       Most  of those values can be changed while corosync is running with the
42       following exceptions: quorum.disallowed cannot be changed, and two_node
43       cannot  be  set  on-the-fly, though it can be cleared. ie you can start
44       with two nodes in the cluster and add a third without rebooting all the
45       nodes.
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BUGS

48       This software is not yet production, so there may still be some bugs.
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SEE ALSO

51       corosync-quorumtool(8),   votequorum_initialize(3),   votequorum_final‐
52       ize(3), votequorum_fd_get(3),  votequorum_dispatch(3),  votequorum_con‐
53       text_get(3), votequorum_context_set(3),
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55corosync Man Page                 2009-01-26            VOTEQUORUM_OVERVIEW(8)
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