Author: buildbot
Date: Mon Jan 5 21:21:40 2015
New Revision: 935180
Log:
Production update by buildbot for activemq
Modified:
websites/production/activemq/content/cache/main.pageCache
websites/production/activemq/content/replicated-leveldb-store.html
Modified: websites/production/activemq/content/cache/main.pageCache
==============================================================================
Binary files - no diff available.
Modified: websites/production/activemq/content/replicated-leveldb-store.html
==============================================================================
--- websites/production/activemq/content/replicated-leveldb-store.html
(original)
+++ websites/production/activemq/content/replicated-leveldb-store.html Mon Jan
5 21:21:40 2015
@@ -81,54 +81,18 @@
<tbody>
<tr>
<td valign="top" width="100%">
-<div class="wiki-content maincontent"><h2
id="ReplicatedLevelDBStore-Synopsis">Synopsis</h2>
-
-<p>The Replicated LevelDB Store uses Apache ZooKeeper to pick a master from a
set of broker nodes configured to replicate a LevelDB Store. Then synchronizes
all slave LevelDB Stores with the master keeps them up to date by replicating
all updates from the master.</p>
-
-<p>The Replicated LevelDB Store uses the same data files as a LevelDB Store,
so you can switch a broker configuration between replicated and non replicated
whenever you want.</p>
-
-
- <div class="aui-message hint shadowed information-macro">
+<div class="wiki-content maincontent"><h2
id="ReplicatedLevelDBStore-Synopsis">Synopsis</h2><p>The Replicated LevelDB
Store uses Apache ZooKeeper to pick a master from a set of broker nodes
configured to replicate a LevelDB Store. Then synchronizes all slave LevelDB
Stores with the master keeps them up to date by replicating all updates from
the master.</p><p>The Replicated LevelDB Store uses the same data files as a
LevelDB Store, so you can switch a broker configuration between replicated and
non replicated whenever you want.</p> <div class="aui-message hint shadowed
information-macro">
<p class="title">Version Compatibility</p>
<span class="aui-icon icon-hint">Icon</span>
<div class="message-content">
-
-<p>Available as of ActiveMQ 5.9.0.</p>
+ <p>Available as of ActiveMQ 5.9.0.</p>
</div>
</div>
-
-
-<h2 id="ReplicatedLevelDBStore-Howitworks.">How it works.</h2>
-
-<p><img class="confluence-embedded-image"
src="https://cwiki.apache.org/confluence/download/attachments/31820167/replicated-leveldb-store.png?version=1&modificationDate=1367958504000&api=v2";
data-image-src="/confluence/download/attachments/31820167/replicated-leveldb-store.png?version=1&modificationDate=1367958504000&api=v2"></p>
-
-<p>It uses <a shape="rect" class="external-link"
href="http://zookeeper.apache.org/";>Apache ZooKeeper</a> to coordinate which
node in the cluster becomes the master. The elected master broker node starts
and accepts client connections. The other nodes go into slave mode and connect
the the master and synchronize their persistent state /w it. The slave nodes
do not accept client connections. All persistent operations are replicated to
the connected slaves. If the master dies, the slaves with the latest update
gets promoted to become the master. The failed node can then be brought back
online and it will go into slave mode.</p>
-
-<p>All messaging operations which require a sync to disk will wait for the
update to be replicated to a quorum of the nodes before completing. So if you
configure the store with <code>replicas="3"</code> then the quorum size is
<code>(3/2+1)=2</code>. The master will store the update locally and wait for
1 other slave to store the update before reporting success. Another way to
think about it is that store will do synchronous replication to a quorum of the
replication nodes and asynchronous replication replication to any additional
nodes.</p>
-
-<p>When a new master is elected, you also need at least a quorum of nodes
online to be able to find a node with the lastest updates. The node with the
lastest updates will become the new master. Therefore, it's recommend that you
run with at least 3 replica nodes so that you can take one down without
suffering a service outage.</p>
-
-<h3 id="ReplicatedLevelDBStore-DeploymentTips">Deployment Tips</h3>
-
-<p>Clients should be using the <a shape="rect"
href="failover-transport-reference.html">Failover Transport</a> to connect to
the broker nodes in the replication cluster. e.g. using a URL something like
the following:</p>
-
-<div class="code panel pdl" style="border-width: 1px;"><div class="codeContent
panelContent pdl">
-<script class="theme: Default; brush: java; gutter: false"
type="syntaxhighlighter"><![CDATA[
-failover:(tcp://broker1:61616,tcp://broker2:61616,tcp://broker3:61616)
+<h2 id="ReplicatedLevelDBStore-Howitworks.">How it works.</h2><p><img
class="confluence-embedded-image"
src="replicated-leveldb-store.data/replicated-leveldb-store.png"
data-image-src="/confluence/download/attachments/31820167/replicated-leveldb-store.png?version=1&modificationDate=1367958504000&api=v2"></p><p>It
uses <a shape="rect" class="external-link"
href="http://zookeeper.apache.org/";>Apache ZooKeeper</a> to coordinate which
node in the cluster becomes the master. The elected master broker node starts
and accepts client connections. The other nodes go into slave mode and connect
the the master and synchronize their persistent state /w it. The slave nodes do
not accept client connections. All persistent operations are replicated to the
connected slaves. If the master dies, the slaves with the latest update gets
promoted to become the master. The failed node can then be brought back online
and it will go into slave mode.</p><p>All messaging operations which require a
syn
c to disk will wait for the update to be replicated to a quorum of the nodes
before completing. So if you configure the store with <code>replicas="3"</code>
then the quorum size is <code>(3/2+1)=2</code>. The master will store the
update locally and wait for 1 other slave to store the update before reporting
success. Another way to think about it is that store will do synchronous
replication to a quorum of the replication nodes and asynchronous replication
replication to any additional nodes.</p><p>When a new master is elected, you
also need at least a quorum of nodes online to be able to find a node with the
lastest updates. The node with the lastest updates will become the new master.
Therefore, it's recommend that you run with at least 3 replica nodes so that
you can take one down without suffering a service outage.</p><h3
id="ReplicatedLevelDBStore-DeploymentTips">Deployment Tips</h3><p>Clients
should be using the <a shape="rect"
href="failover-transport-reference.html">Failover
Transport</a> to connect to the broker nodes in the replication cluster. e.g.
using a URL something like the following:</p><div class="code panel pdl"
style="border-width: 1px;"><div class="codeContent panelContent pdl">
+<script class="theme: Default; brush: java; gutter: false"
type="syntaxhighlighter"><![CDATA[failover:(tcp://broker1:61616,tcp://broker2:61616,tcp://broker3:61616)
]]></script>
-</div></div>
-
-<p>You should run at least 3 ZooKeeper server nodes so that the ZooKeeper
service is highly available. Don't overcommit your ZooKeeper servers. An
overworked ZooKeeper might start thinking live replication nodes have gone
offline due to delays in processing their 'keep-alive' messages.</p>
-
-<p>For best results, make sure you explicitly configure the hostname attribute
with a hostname or ip address for the node that other cluster members to access
the machine with. The automatically determined hostname is not always
accessible by the other cluster members and results in slaves not being able to
establish a replication session with the master.</p>
-
-<h2 id="ReplicatedLevelDBStore-Configuration">Configuration</h2>
-
-<p>You can configure ActiveMQ to use LevelDB for its persistence adapter -
like below :</p>
-
-<div class="code panel pdl" style="border-width: 1px;"><div class="codeContent
panelContent pdl">
-<script class="theme: Default; brush: java; gutter: false"
type="syntaxhighlighter"><![CDATA[
- <broker brokerName="broker" ... >
+</div></div><p>You should run at least 3 ZooKeeper server nodes so that the
ZooKeeper service is highly available. Don't overcommit your ZooKeeper servers.
An overworked ZooKeeper might start thinking live replication nodes have gone
offline due to delays in processing their 'keep-alive' messages.</p><p>For best
results, make sure you explicitly configure the hostname attribute with a
hostname or ip address for the node that other cluster members to access the
machine with. The automatically determined hostname is not always accessible by
the other cluster members and results in slaves not being able to establish a
replication session with the master.</p><h2
id="ReplicatedLevelDBStore-Configuration">Configuration</h2><p>You can
configure ActiveMQ to use LevelDB for its persistence adapter - like below
:</p><div class="code panel pdl" style="border-width: 1px;"><div
class="codeContent panelContent pdl">
+<script class="theme: Default; brush: java; gutter: false"
type="syntaxhighlighter"><![CDATA[ <broker brokerName="broker"
... >
...
<persistenceAdapter>
<replicatedLevelDB
@@ -144,37 +108,11 @@ failover:(tcp://broker1:61616,tcp://brok
...
</broker>
]]></script>
-</div></div>
-
-<h3 id="ReplicatedLevelDBStore-ReplicatedLevelDBStoreProperties">Replicated
LevelDB Store Properties</h3>
-
-<p>All the broker nodes that are part of the same replication set should have
matching <code>brokerName</code> XML attributes. The following configuration
properties should be the same on all the broker nodes that are part of the same
replication set:</p>
-
-<div class="table-wrap"><table class="confluenceTable"><tbody><tr><th
colspan="1" rowspan="1" class="confluenceTh"><p> property name </p></th><th
colspan="1" rowspan="1" class="confluenceTh"><p> default value </p></th><th
colspan="1" rowspan="1" class="confluenceTh"><p> Comments </p></th></tr><tr><td
colspan="1" rowspan="1" class="confluenceTd"><p> <code>replicas</code>
</p></td><td colspan="1" rowspan="1" class="confluenceTd"><p> <code>3</code>
</p></td><td colspan="1" rowspan="1" class="confluenceTd"><p> The number of
nodes that will exist in the cluster. At least (replicas/2)+1 nodes must be
online to avoid service outage. </p></td></tr><tr><td colspan="1" rowspan="1"
class="confluenceTd"><p> <code>securityToken</code> </p></td><td colspan="1"
rowspan="1" class="confluenceTd"><p> </p></td><td colspan="1" rowspan="1"
class="confluenceTd"><p> A security token which must match on all replication
nodes for them to accept each others replication requests.
</p></td></tr><tr><td c
olspan="1" rowspan="1" class="confluenceTd"><p> <code>zkAddress</code>
</p></td><td colspan="1" rowspan="1" class="confluenceTd"><p>
<code>127.0.0.1:2181</code> </p></td><td colspan="1" rowspan="1"
class="confluenceTd"><p> A comma separated list of ZooKeeper servers.
</p></td></tr><tr><td colspan="1" rowspan="1" class="confluenceTd"><p>
<code>zkPassword</code> </p></td><td colspan="1" rowspan="1"
class="confluenceTd"><p> </p></td><td colspan="1" rowspan="1"
class="confluenceTd"><p> The password to use when connecting to the ZooKeeper
server. </p></td></tr><tr><td colspan="1" rowspan="1" class="confluenceTd"><p>
<code>zkPath</code> </p></td><td colspan="1" rowspan="1"
class="confluenceTd"><p> <code>/default</code> </p></td><td colspan="1"
rowspan="1" class="confluenceTd"><p> The path to the ZooKeeper directory where
Master/Slave election information will be exchanged. </p></td></tr><tr><td
colspan="1" rowspan="1" class="confluenceTd"><p> <code>zkSessionTmeout</code>
</p></td><td
colspan="1" rowspan="1" class="confluenceTd"><p> <code>2s</code> </p></td><td
colspan="1" rowspan="1" class="confluenceTd"><p> How quickly a node failure
will be detected by ZooKeeper. </p></td></tr><tr><td colspan="1" rowspan="1"
class="confluenceTd"><p> <code>sync</code> </p></td><td colspan="1" rowspan="1"
class="confluenceTd"><p> <code>quorum_mem</code> </p></td><td colspan="1"
rowspan="1" class="confluenceTd"><p> Controls where updates are reside before
being considered complete. This setting is a comma separated list of the
following options: <code>local_mem</code>, <code>local_disk</code>,
<code>remote_mem</code>, <code>remote_disk</code>, <code>quorum_mem</code>,
<code>quorum_disk</code>. If you combine two settings for a target, the
stronger guarantee is used. For example, configuring <code>local_mem,
local_disk</code> is the same as just using <code>local_disk</code>.
quorum_mem is the same as <code>local_mem, remote_mem</code> and
<code>quorum_disk</code> is the same a
s <code>local_disk, remote_disk</code> </p></td></tr></tbody></table></div>
-
-
-
-<p>Different replication sets can share the same <code>zkPath</code> as long
they have different <code>brokerName</code>.</p>
-
-<p>The following configuration properties can be unique per node:</p>
-
-<div class="table-wrap"><table class="confluenceTable"><tbody><tr><th
colspan="1" rowspan="1" class="confluenceTh"><p> property name </p></th><th
colspan="1" rowspan="1" class="confluenceTh"><p> default value </p></th><th
colspan="1" rowspan="1" class="confluenceTh"><p> Comments </p></th></tr><tr><td
colspan="1" rowspan="1" class="confluenceTd"><p> <code>bind</code> </p></td><td
colspan="1" rowspan="1" class="confluenceTd"><p>
<code>tcp://0.0.0.0:61619</code> </p></td><td colspan="1" rowspan="1"
class="confluenceTd"><p> When this node becomes a master, it will bind the
configured address and port to service the replication protocol. Using dynamic
ports is also supported. Just configure with <code>tcp://0.0.0.0:0</code>
</p></td></tr><tr><td colspan="1" rowspan="1" class="confluenceTd"><p>
<code>hostname</code> </p></td><td colspan="1" rowspan="1"
class="confluenceTd"><p> </p></td><td colspan="1" rowspan="1"
class="confluenceTd"><p> The host name used to advertise the replicat
ion service when this node becomes the master. If not set it will be
automatically determined. </p></td></tr><tr><td colspan="1" rowspan="1"
class="confluenceTd"><p> <code>weight</code> </p></td><td colspan="1"
rowspan="1" class="confluenceTd"><p> 1 </p></td><td colspan="1" rowspan="1"
class="confluenceTd"><p> The replication node that has the latest update with
the highest weight will become the master. Used to give preference to some
nodes towards becoming master. </p></td></tr></tbody></table></div>
-
-
-<p>The store also supports the same configuration properties of a standard <a
shape="rect" href="leveldb-store.html">LevelDB Store</a> but it does not
support the pluggable storage lockers :</p>
-
-<h3 id="ReplicatedLevelDBStore-StandardLevelDBStoreProperties">Standard
LevelDB Store Properties</h3>
-
-<div class="table-wrap"><table class="confluenceTable"><tbody><tr><th
colspan="1" rowspan="1" class="confluenceTh"><p> property name </p></th><th
colspan="1" rowspan="1" class="confluenceTh"><p> default value </p></th><th
colspan="1" rowspan="1" class="confluenceTh"><p> Comments </p></th></tr><tr><td
colspan="1" rowspan="1" class="confluenceTd"><p> <code>directory</code>
</p></td><td colspan="1" rowspan="1" class="confluenceTd"><p>
<code>LevelDB</code> </p></td><td colspan="1" rowspan="1"
class="confluenceTd"><p> The directory which the store will use to hold it's
data files. The store will create the directory if it does not already exist.
</p></td></tr><tr><td colspan="1" rowspan="1" class="confluenceTd"><p>
<code>readThreads</code> </p></td><td colspan="1" rowspan="1"
class="confluenceTd"><p> <code>10</code> </p></td><td colspan="1" rowspan="1"
class="confluenceTd"><p> The number of concurrent IO read threads to allowed.
</p></td></tr><tr><td colspan="1" rowspan="1" class="conflu
enceTd"><p> <code>logSize</code> </p></td><td colspan="1" rowspan="1"
class="confluenceTd"><p> <code>104857600</code> (100 MB) </p></td><td
colspan="1" rowspan="1" class="confluenceTd"><p> The max size (in bytes) of
each data log file before log file rotation occurs. </p></td></tr><tr><td
colspan="1" rowspan="1" class="confluenceTd"><p>
<code>logWriteBufferSize</code> </p></td><td colspan="1" rowspan="1"
class="confluenceTd"><p> <code>4194304</code> (4 MB) </p></td><td colspan="1"
rowspan="1" class="confluenceTd"><p> That maximum amount of log data to build
up before writing to the file system. </p></td></tr><tr><td colspan="1"
rowspan="1" class="confluenceTd"><p> <code>verifyChecksums</code> </p></td><td
colspan="1" rowspan="1" class="confluenceTd"><p> <code>false</code>
</p></td><td colspan="1" rowspan="1" class="confluenceTd"><p> Set to true to
force checksum verification of all data that is read from the file system.
</p></td></tr><tr><td colspan="1" rowspan="1" class="confluenc
eTd"><p> <code>paranoidChecks</code> </p></td><td colspan="1" rowspan="1"
class="confluenceTd"><p> <code>false</code> </p></td><td colspan="1"
rowspan="1" class="confluenceTd"><p> Make the store error out as soon as
possible if it detects internal corruption. </p></td></tr><tr><td colspan="1"
rowspan="1" class="confluenceTd"><p> <code>indexFactory</code> </p></td><td
colspan="1" rowspan="1" class="confluenceTd"><p>
<code>org.fusesource.leveldbjni.JniDBFactory,
org.iq80.leveldb.impl.Iq80DBFactory</code> </p></td><td colspan="1" rowspan="1"
class="confluenceTd"><p> The factory classes to use when creating the LevelDB
indexes </p></td></tr><tr><td colspan="1" rowspan="1" class="confluenceTd"><p>
<code>indexMaxOpenFiles</code> </p></td><td colspan="1" rowspan="1"
class="confluenceTd"><p> <code>1000</code> </p></td><td colspan="1" rowspan="1"
class="confluenceTd"><p> Number of open files that can be used by the index.
</p></td></tr><tr><td colspan="1" rowspan="1" class="confluenceTd"><p>
<code>indexBlockRestartInterval</code> </p></td><td colspan="1" rowspan="1"
class="confluenceTd"><p> <code>16</code> </p></td><td colspan="1" rowspan="1"
class="confluenceTd"><p> Number keys between restart points for delta encoding
of keys. </p></td></tr><tr><td colspan="1" rowspan="1" class="confluenceTd"><p>
<code>indexWriteBufferSize</code> </p></td><td colspan="1" rowspan="1"
class="confluenceTd"><p> <code>6291456</code> (6 MB) </p></td><td colspan="1"
rowspan="1" class="confluenceTd"><p> Amount of index data to build up in memory
before converting to a sorted on-disk file. </p></td></tr><tr><td colspan="1"
rowspan="1" class="confluenceTd"><p> <code>indexBlockSize</code> </p></td><td
colspan="1" rowspan="1" class="confluenceTd"><p> <code>4096</code> (4 K)
</p></td><td colspan="1" rowspan="1" class="confluenceTd"><p> The size of index
data packed per block. </p></td></tr><tr><td colspan="1" rowspan="1"
class="confluenceTd"><p> <code>indexCacheSize</code> </p></td><td colspan="1
" rowspan="1" class="confluenceTd"><p> <code>268435456</code> (256 MB)
</p></td><td colspan="1" rowspan="1" class="confluenceTd"><p> The maximum
amount of off-heap memory to use to cache index blocks. </p></td></tr><tr><td
colspan="1" rowspan="1" class="confluenceTd"><p> <code>indexCompression</code>
</p></td><td colspan="1" rowspan="1" class="confluenceTd"><p>
<code>snappy</code> </p></td><td colspan="1" rowspan="1"
class="confluenceTd"><p> The type of compression to apply to the index blocks.
Can be snappy or none. </p></td></tr><tr><td colspan="1" rowspan="1"
class="confluenceTd"><p> <code>logCompression</code> </p></td><td colspan="1"
rowspan="1" class="confluenceTd"><p> <code>none</code> </p></td><td colspan="1"
rowspan="1" class="confluenceTd"><p> The type of compression to apply to the
log records. Can be snappy or none. </p></td></tr></tbody></table></div>
-
-
-
- <div class="aui-message problem shadowed information-macro">
+</div></div><h3
id="ReplicatedLevelDBStore-ReplicatedLevelDBStoreProperties">Replicated LevelDB
Store Properties</h3><p>All the broker nodes that are part of the same
replication set should have matching <code>brokerName</code> XML attributes.
The following configuration properties should be the same on all the broker
nodes that are part of the same replication set:</p><div
class="table-wrap"><table class="confluenceTable"><tbody><tr><th colspan="1"
rowspan="1" class="confluenceTh"><p>property name</p></th><th colspan="1"
rowspan="1" class="confluenceTh"><p>default value</p></th><th colspan="1"
rowspan="1" class="confluenceTh"><p>Comments</p></th></tr><tr><td colspan="1"
rowspan="1" class="confluenceTd"><p><code>replicas</code></p></td><td
colspan="1" rowspan="1" class="confluenceTd"><p><code>3</code></p></td><td
colspan="1" rowspan="1" class="confluenceTd"><p>The number of nodes that will
exist in the cluster. At least (replicas/2)+1 nodes must be online to avoid
service outage.</p
></td></tr><tr><td colspan="1" rowspan="1"
>class="confluenceTd"><p><code>securityToken</code></p></td><td colspan="1"
>rowspan="1" class="confluenceTd"><p> </p></td><td colspan="1"
>rowspan="1" class="confluenceTd"><p>A security token which must match on all
>replication nodes for them to accept each others replication
>requests.</p></td></tr><tr><td colspan="1" rowspan="1"
>class="confluenceTd"><p><code>zkAddress</code></p></td><td colspan="1"
>rowspan="1" class="confluenceTd"><p><code>127.0.0.1:2181</code></p></td><td
>colspan="1" rowspan="1" class="confluenceTd"><p>A comma separated list of
>ZooKeeper servers.</p></td></tr><tr><td colspan="1" rowspan="1"
>class="confluenceTd"><p><code>zkPassword</code></p></td><td colspan="1"
>rowspan="1" class="confluenceTd"><p> </p></td><td colspan="1"
>rowspan="1" class="confluenceTd"><p>The password to use when connecting to
>the ZooKeeper server.</p></td></tr><tr><td colspan="1" rowspan="1"
>class="confluenceTd"><p><code>zkPath</code></p></td><
td colspan="1" rowspan="1"
class="confluenceTd"><p><code>/default</code></p></td><td colspan="1"
rowspan="1" class="confluenceTd"><p>The path to the ZooKeeper directory where
Master/Slave election information will be exchanged.</p></td></tr><tr><td
colspan="1" rowspan="1"
class="confluenceTd"><p><code>zkSessionTimeout</code></p></td><td colspan="1"
rowspan="1" class="confluenceTd"><p><code>2s</code></p></td><td colspan="1"
rowspan="1" class="confluenceTd"><p>How quickly a node failure will be detected
by ZooKeeper. (prior to 5.11 - this had a typo
<span>zkSessionTmeout)</span></p></td></tr><tr><td colspan="1" rowspan="1"
class="confluenceTd"><p><code>sync</code></p></td><td colspan="1" rowspan="1"
class="confluenceTd"><p><code>quorum_mem</code></p></td><td colspan="1"
rowspan="1" class="confluenceTd"><p>Controls where updates are reside before
being considered complete. This setting is a comma separated list of the
following options: <code>local_mem</code>, <code>local_disk</code>,
<code>remote_mem</code>, <code>remote_disk</code>, <code>quorum_mem</code>,
<code>quorum_disk</code>. If you combine two settings for a target, the
stronger guarantee is used. For example, configuring <code>local_mem,
local_disk</code> is the same as just using <code>local_disk</code>. quorum_mem
is the same as <code>local_mem, remote_mem</code> and <code>quorum_disk</code>
is the same as <code>local_disk,
remote_disk</code></p></td></tr></tbody></table></div><p>Different replication
sets can share the same <code>zkPath</code> as long they have different
<code>brokerName</code>.</p><p>The following configuration properties can be
unique per node:</p><div class="table-wrap"><table
class="confluenceTable"><tbody><tr><th colspan="1" rowspan="1"
class="confluenceTh"><p>property name</p></th><th colspan="1" rowspan="1"
class="confluenceTh"><p>default value</p></th><th colspan="1" rowspan="1"
class="confluenceTh"><p>Comments</p></th></tr><tr><td colspan="1" rowspan="1"
class="confluenceTd
"><p><code>bind</code></p></td><td colspan="1" rowspan="1"
class="confluenceTd"><p><code>tcp://0.0.0.0:61619</code></p></td><td
colspan="1" rowspan="1" class="confluenceTd"><p>When this node becomes a
master, it will bind the configured address and port to service the replication
protocol. Using dynamic ports is also supported. Just configure with
<code>tcp://0.0.0.0:0</code></p></td></tr><tr><td colspan="1" rowspan="1"
class="confluenceTd"><p><code>hostname</code></p></td><td colspan="1"
rowspan="1" class="confluenceTd"><p> </p></td><td colspan="1" rowspan="1"
class="confluenceTd"><p>The host name used to advertise the replication service
when this node becomes the master. If not set it will be automatically
determined.</p></td></tr><tr><td colspan="1" rowspan="1"
class="confluenceTd"><p><code>weight</code></p></td><td colspan="1" rowspan="1"
class="confluenceTd"><p>1</p></td><td colspan="1" rowspan="1"
class="confluenceTd"><p>The replication node that has the latest update wi
th the highest weight will become the master. Used to give preference to some
nodes towards becoming master.</p></td></tr></tbody></table></div><p>The store
also supports the same configuration properties of a standard <a shape="rect"
href="leveldb-store.html">LevelDB Store</a> but it does not support the
pluggable storage lockers :</p><h3
id="ReplicatedLevelDBStore-StandardLevelDBStoreProperties">Standard LevelDB
Store Properties</h3><div class="table-wrap"><table
class="confluenceTable"><tbody><tr><th colspan="1" rowspan="1"
class="confluenceTh"><p>property name</p></th><th colspan="1" rowspan="1"
class="confluenceTh"><p>default value</p></th><th colspan="1" rowspan="1"
class="confluenceTh"><p>Comments</p></th></tr><tr><td colspan="1" rowspan="1"
class="confluenceTd"><p><code>directory</code></p></td><td colspan="1"
rowspan="1" class="confluenceTd"><p><code>LevelDB</code></p></td><td
colspan="1" rowspan="1" class="confluenceTd"><p>The directory which the store
will use to hold it'
s data files. The store will create the directory if it does not already
exist.</p></td></tr><tr><td colspan="1" rowspan="1"
class="confluenceTd"><p><code>readThreads</code></p></td><td colspan="1"
rowspan="1" class="confluenceTd"><p><code>10</code></p></td><td colspan="1"
rowspan="1" class="confluenceTd"><p>The number of concurrent IO read threads to
allowed.</p></td></tr><tr><td colspan="1" rowspan="1"
class="confluenceTd"><p><code>logSize</code></p></td><td colspan="1"
rowspan="1" class="confluenceTd"><p><code>104857600</code> (100 MB)</p></td><td
colspan="1" rowspan="1" class="confluenceTd"><p>The max size (in bytes) of each
data log file before log file rotation occurs.</p></td></tr><tr><td colspan="1"
rowspan="1" class="confluenceTd"><p><code>logWriteBufferSize</code></p></td><td
colspan="1" rowspan="1" class="confluenceTd"><p><code>4194304</code> (4
MB)</p></td><td colspan="1" rowspan="1" class="confluenceTd"><p>That maximum
amount of log data to build up before writing to th
e file system.</p></td></tr><tr><td colspan="1" rowspan="1"
class="confluenceTd"><p><code>verifyChecksums</code></p></td><td colspan="1"
rowspan="1" class="confluenceTd"><p><code>false</code></p></td><td colspan="1"
rowspan="1" class="confluenceTd"><p>Set to true to force checksum verification
of all data that is read from the file system.</p></td></tr><tr><td colspan="1"
rowspan="1" class="confluenceTd"><p><code>paranoidChecks</code></p></td><td
colspan="1" rowspan="1" class="confluenceTd"><p><code>false</code></p></td><td
colspan="1" rowspan="1" class="confluenceTd"><p>Make the store error out as
soon as possible if it detects internal corruption.</p></td></tr><tr><td
colspan="1" rowspan="1"
class="confluenceTd"><p><code>indexFactory</code></p></td><td colspan="1"
rowspan="1"
class="confluenceTd"><p><code>org.fusesource.leveldbjni.JniDBFactory,
org.iq80.leveldb.impl.Iq80DBFactory</code></p></td><td colspan="1" rowspan="1"
class="confluenceTd"><p>The factory classes to use when cre
ating the LevelDB indexes</p></td></tr><tr><td colspan="1" rowspan="1"
class="confluenceTd"><p><code>indexMaxOpenFiles</code></p></td><td colspan="1"
rowspan="1" class="confluenceTd"><p><code>1000</code></p></td><td colspan="1"
rowspan="1" class="confluenceTd"><p>Number of open files that can be used by
the index.</p></td></tr><tr><td colspan="1" rowspan="1"
class="confluenceTd"><p><code>indexBlockRestartInterval</code></p></td><td
colspan="1" rowspan="1" class="confluenceTd"><p><code>16</code></p></td><td
colspan="1" rowspan="1" class="confluenceTd"><p>Number keys between restart
points for delta encoding of keys.</p></td></tr><tr><td colspan="1" rowspan="1"
class="confluenceTd"><p><code>indexWriteBufferSize</code></p></td><td
colspan="1" rowspan="1" class="confluenceTd"><p><code>6291456</code> (6
MB)</p></td><td colspan="1" rowspan="1" class="confluenceTd"><p>Amount of index
data to build up in memory before converting to a sorted on-disk
file.</p></td></tr><tr><td colspan="1" row
span="1" class="confluenceTd"><p><code>indexBlockSize</code></p></td><td
colspan="1" rowspan="1" class="confluenceTd"><p><code>4096</code> (4
K)</p></td><td colspan="1" rowspan="1" class="confluenceTd"><p>The size of
index data packed per block.</p></td></tr><tr><td colspan="1" rowspan="1"
class="confluenceTd"><p><code>indexCacheSize</code></p></td><td colspan="1"
rowspan="1" class="confluenceTd"><p><code>268435456</code> (256 MB)</p></td><td
colspan="1" rowspan="1" class="confluenceTd"><p>The maximum amount of off-heap
memory to use to cache index blocks.</p></td></tr><tr><td colspan="1"
rowspan="1" class="confluenceTd"><p><code>indexCompression</code></p></td><td
colspan="1" rowspan="1" class="confluenceTd"><p><code>snappy</code></p></td><td
colspan="1" rowspan="1" class="confluenceTd"><p>The type of compression to
apply to the index blocks. Can be snappy or none.</p></td></tr><tr><td
colspan="1" rowspan="1"
class="confluenceTd"><p><code>logCompression</code></p></td><td colspan="
1" rowspan="1" class="confluenceTd"><p><code>none</code></p></td><td
colspan="1" rowspan="1" class="confluenceTd"><p>The type of compression to
apply to the log records. Can be snappy or
none.</p></td></tr></tbody></table></div> <div class="aui-message problem
shadowed information-macro">
<p class="title">Caveats</p>
<span class="aui-icon icon-problem">Icon</span>
<div class="message-content">
-
-<p>The LevelDB store does not yet support storing data associated with <a
shape="rect" href="delay-and-schedule-message-delivery.html">Delay and Schedule
Message Delivery</a>. Those are are stored in a separate non-replicated KahaDB
data files. Unexpected results will occur if you use <a shape="rect"
href="delay-and-schedule-message-delivery.html">Delay and Schedule Message
Delivery</a> with the replicated leveldb store since that data will be not be
there when the master fails over to a slave.</p>
+ <p>The LevelDB store does not yet support storing
data associated with <a shape="rect"
href="delay-and-schedule-message-delivery.html">Delay and Schedule Message
Delivery</a>. Those are are stored in a separate non-replicated KahaDB data
files. Unexpected results will occur if you use <a shape="rect"
href="delay-and-schedule-message-delivery.html">Delay and Schedule Message
Delivery</a> with the replicated leveldb store since that data will be not be
there when the master fails over to a slave.</p>
</div>
</div></div>
</td>
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