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Posted to commits@kafka.apache.org by gu...@apache.org on 2018/06/26 15:24:54 UTC
[kafka] branch trunk updated: MINOR: Add note about
num.standby.replicas (#5271)
This is an automated email from the ASF dual-hosted git repository.
guozhang pushed a commit to branch trunk
in repository https://gitbox.apache.org/repos/asf/kafka.git
The following commit(s) were added to refs/heads/trunk by this push:
new 581adb5 MINOR: Add note about num.standby.replicas (#5271)
581adb5 is described below
commit 581adb5013ed996705031ca8dd9e175c40675692
Author: Jim Galasyn <ji...@confluent.io>
AuthorDate: Tue Jun 26 08:24:44 2018 -0700
MINOR: Add note about num.standby.replicas (#5271)
Reviewers: Guozhang Wang <wa...@gmail.com>
---
docs/streams/developer-guide/config-streams.html | 9 +++++++--
1 file changed, 7 insertions(+), 2 deletions(-)
diff --git a/docs/streams/developer-guide/config-streams.html b/docs/streams/developer-guide/config-streams.html
index 2c6bce1..5f9834b 100644
--- a/docs/streams/developer-guide/config-streams.html
+++ b/docs/streams/developer-guide/config-streams.html
@@ -418,12 +418,17 @@
<span id="streams-developer-guide-standby-replicas"></span><h4><a class="toc-backref" href="#id10">num.standby.replicas</a><a class="headerlink" href="#num-standby-replicas" title="Permalink to this headline"></a></h4>
<blockquote>
<div>The number of standby replicas. Standby replicas are shadow copies of local state stores. Kafka Streams attempts to create the
- specified number of replicas and keep them up to date as long as there are enough instances running.
+ specified number of replicas per store and keep them up to date as long as there are enough instances running.
Standby replicas are used to minimize the latency of task failover. A task that was previously running on a failed instance is
preferred to restart on an instance that has standby replicas so that the local state store restoration process from its
changelog can be minimized. Details about how Kafka Streams makes use of the standby replicas to minimize the cost of
resuming tasks on failover can be found in the <a class="reference internal" href="../architecture.html#streams_architecture_state"><span class="std std-ref">State</span></a> section.</div></blockquote>
- </div>
+ </div>
+ <div class="admonition note">
+ <p class="first admonition-title">Note</p>
+ <p class="last">If you enable <cite>n</cite> standby tasks, you need to provision <cite>n+1</cite> <code class="docutils literal"><span class="pre">KafkaStreams</span></code>
+ instances.</p>
+ </div>
<div class="section" id="num-stream-threads">
<h4><a class="toc-backref" href="#id11">num.stream.threads</a><a class="headerlink" href="#num-stream-threads" title="Permalink to this headline"></a></h4>
<blockquote>