[[_clustering_db_lock]]
=== Serialized Cluster Startup

{{book.project.name}} cluster nodes are allowed to boot concurrenty.
When {{book.project.name}} server instance boots up it may do some database migration, importing, or first time initializations.
A DB lock is used to prevent start actions from conflicting with one another when cluster nodes boot up concurrently.

By default, the maximum timeout for this lock is 900 seconds.  If a node is waiting on this lock for more than the timeout
it will fail to boot.
Typically you won't need to increase/decrease the default value, but just in case it's possible to configure it in 
`standalone.xml`, `standalone-ha.xml`, or `domain.xml` file in your distribution.  The location of this file 
depends on your <<fake/../../operating-mode.adoc#_operating-mode, operating mode>>. 

[source,xml]
----
<spi name="dblock">
    <provider name="jpa" enabled="true">
        <properties>
            <property name="lockWaitTimeout" value="900"/>
        </properties>
    </provider>
</spi>
----