HBASE-11736 Document SKIP_FLUSH snapshot option (Misty Stanley-Jones)

This commit is contained in:
Matteo Bertozzi 2014-08-20 09:46:56 +01:00
parent a55a65017c
commit dd3c9da27a
1 changed files with 19 additions and 0 deletions

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@ -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'
</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">