Create basic directory structure

All new features specs go into in_progress directory.
Once signed off, it should be moved to done directory.

For now,
This change moves all the Gluster 4.0 feature specs to
in_progress. All other specs are under done/release-version.

More cleanup required will be done incrementally.

Change-Id: Id272d301ba8c434cbf7a9a966ceba05fe63b230d
BUG: 1206539
Signed-off-by: Raghavendra Talur <rtalur@redhat.com>
Reviewed-on: http://review.gluster.org/11969
Reviewed-by: Humble Devassy Chirammal <humble.devassy@gmail.com>
Reviewed-by: Prashanth Pai <ppai@redhat.com>
Tested-by: Humble Devassy Chirammal <humble.devassy@gmail.com>

1 files changed, 44 insertions, 0 deletions

diff --git a/done/Features/server-quorum.md b/done/Features/server-quorum.md
new file mode 100644
index 0000000..7b20084
--- /dev/null
+++ b/done/Features/server-quorum.md
@@ -0,0 +1,44 @@
+# Server Quorum
+
+Server quorum is a feature intended to reduce the occurrence of "split brain"
+after a brick failure or network partition.  Split brain happens when different
+sets of servers are allowed to process different sets of writes, leaving data
+in a state that can not be reconciled automatically.  The key to avoiding split
+brain is to ensure that there can be only one set of servers - a quorum - that
+can continue handling writes.  Server quorum does this by the brutal but
+effective means of forcing down all brick daemons on cluster nodes that can no
+longer reach enough of their peers to form a majority.  Because there can only
+be one majority, there can be only one set of bricks remaining, and thus split
+brain can not occur.
+
+## Options
+
+Server quorum is controlled by two parameters:
+
+ * **cluster.server-quorum-type**
+ 
+   This value may be "server" to indicate that server quorum is enabled, or
+   "none" to mean it's disabled.
+	
+ * **cluster.server-quorum-ratio**
+
+   This is the percentage of cluster nodes that must be up to maintain quorum.
+   More precisely, this percentage of nodes *plus one* must be up.
+
+Note that these are cluster-wide flags.  All volumes served by the cluster will
+be affected.  Once these values are set, quorum actions - starting or stopping
+brick daemons in response to node or network events - will be automatic.
+
+## Best Practices
+
+If a cluster with an even number of nodes is split exactly down the middle,
+neither half can have quorum (which requires **more than** half of the total).
+This is particularly important when N=2, in which case the loss of either node
+leads to loss of quorum.  Therefore, it is highly advisable to ensure that the
+cluster size is three or greater.  The "extra" node in this case need not have
+any bricks or serve any data.  It need only be present to preserve the notion
+of a quorum majority less than the entire cluster membership, allowing the
+cluster to survive the loss of a single node without losing quorum.
+
+
+