From dd3c9da27a4864ade4e3ac2209d081d42353ccf2 Mon Sep 17 00:00:00 2001 From: Matteo Bertozzi Date: Wed, 20 Aug 2014 09:46:56 +0100 Subject: [PATCH] HBASE-11736 Document SKIP_FLUSH snapshot option (Misty Stanley-Jones) --- 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 ac45ecf5556..923872c4279 100644 --- a/src/main/docbkx/ops_mgt.xml +++ b/src/main/docbkx/ops_mgt.xml @@ -1853,6 +1853,25 @@ $ for i in `cat conf/regionservers|sort`; do ./bin/graceful_stop.sh --restart -- $ ./bin/hbase shell hbase> snapshot 'myTable', 'myTableSnapshot-122112' + + Take a Snapshot Without Flushing + 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 of the + snapshot command to disable and flushing while taking the + snapshot. + + hbase> snapshot 'mytable', 'snapshot123', {SKIP_FLUSH => true} + + 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. +