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.berto...@cloudera.com> Authored: Wed Aug 20 09:46:56 2014 +0100 Committer: Matteo Bertozzi <matteo.berto...@cloudera.com> Committed: Wed Aug 20 09:47:39 2014 +0100 ---------------------------------------------------------------------- src/main/docbkx/ops_mgt.xml | 19 +++++++++++++++++++ 1 file changed, 19 insertions(+) ---------------------------------------------------------------------- http://git-wip-us.apache.org/repos/asf/hbase/blob/aee3990e/src/main/docbkx/ops_mgt.xml ---------------------------------------------------------------------- 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' </screen> + <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 excluded + 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 the + 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 other + factors. There is also no way to know whether a given insert or update is in memory or has + been flushed.</para> + </warning> </section> <section xml:id="ops.snapshots.list">
