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From mberto...@apache.org
Subject [2/2] git commit: HBASE-11736 Document SKIP_FLUSH snapshot option (Misty Stanley-Jones)
Date Wed, 20 Aug 2014 08:48:37 GMT
HBASE-11736 Document SKIP_FLUSH snapshot option (Misty Stanley-Jones)

Project: http://git-wip-us.apache.org/repos/asf/hbase/repo
Commit: http://git-wip-us.apache.org/repos/asf/hbase/commit/aee3990e
Tree: http://git-wip-us.apache.org/repos/asf/hbase/tree/aee3990e
Diff: http://git-wip-us.apache.org/repos/asf/hbase/diff/aee3990e

Branch: refs/heads/branch-1
Commit: aee3990eb50ce526e7b90da371b2e522abb802b4
Parents: 5c1ae84
Author: Matteo Bertozzi <matteo.bertozzi@cloudera.com>
Authored: Wed Aug 20 09:46:56 2014 +0100
Committer: Matteo Bertozzi <matteo.bertozzi@cloudera.com>
Committed: Wed Aug 20 09:47:39 2014 +0100

 src/main/docbkx/ops_mgt.xml | 19 +++++++++++++++++++
 1 file changed, 19 insertions(+)

diff --git a/src/main/docbkx/ops_mgt.xml b/src/main/docbkx/ops_mgt.xml
index 8c04c9a..1d515f8 100644
--- a/src/main/docbkx/ops_mgt.xml
+++ b/src/main/docbkx/ops_mgt.xml
@@ -1369,6 +1369,25 @@ $ for i in `cat conf/regionservers|sort`; do ./bin/graceful_stop.sh
--restart --
 $ ./bin/hbase shell
 hbase> snapshot 'myTable', 'myTableSnapshot-122112'
+      <formalpara>
+        <title>Take a Snapshot Without Flushing</title>
+        <para>The default behavior is to perform a flush of data in memory before the
snapshot is
+          taken. This means that data in memory is included in the snapshot. In most cases,
this is
+          the desired behavior. However, if your set-up can tolerate data in memory being
+          from the snapshot, you can use the <option>SKIP_FLUSH</option> option
of the
+            <command>snapshot</command> command to disable and flushing while
taking the
+          snapshot.</para>
+      </formalpara>
+      <screen>hbase> snapshot 'mytable', 'snapshot123', {SKIP_FLUSH => true}</screen>
+      <warning>
+        <para>There is no way to determine or predict whether a very concurrent insert
or update
+          will be included in a given snapshot, whether flushing is enabled or disabled.
A snapshot
+          is only a representation of a table during a window of time. The amount of time
+          snapshot operation will take to reach each Region Server may vary from a few seconds
to a
+          minute, depending on the resource load and speed of the hardware or network, among
+          factors. There is also no way to know whether a given insert or update is in memory
or has
+          been flushed.</para>
+      </warning>

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