Starting with 5.3.1, ActiveMQ provides configurable IOException handling for its file-based message stores. From version 5.5 the handler is also invoked when the JDBC persistence adapter gets a failure on getConnection().

Default IOException handler

ActiveMQ comes with a default IOException handler, which does the following. When some of the file-based message stores encounter IOException it can be one of the two things: either the disk is unavailable of there's no more space on the disk.

The first case is usually encountered when disk fails or network disk is disconnected. These errors are not "recoverable" and we usually want to shutdown the broker until problems with the disk are solved.

When there's no more space on the disk, we usually want to wait that some space is reclaimed and continue what we have been doing before (exchanging messages). All file-based persistent stores are capable of surviving these kind of errors.

Configuring Default IOException handler

There are a couple of properties you can use to tune the behavior of the DefaultIOExceptionHandler. First, instantiate the exception handler as a bean. Then configure the broker to use the exception handler by setting the broker's ioExceptionHandler property.

Example:

Handler configuration properties:

Property

Default Value

Description

ignoreAllErrors

false

When true all errors are ignored and the broker remains running.

ignoreNoSpaceErrors

true

When false 'no disk space' errors are treated the same as other errors causing the broker to be stopped.

noSpaceMessage

space

The string used to match against the exception's message. When matched a 'no disk space' error results.

ignoreSQLExceptions

true

If true all SQLExceptions are ignored by the handler allowing them to be handled by the persistence adapter's locker. When false the exception handler processes the exception.

sqlExceptionMessage

""

The SQLException phrase to match when ignoring SQLExceptions. Only matched exceptions are ignored. All SQLExceptions match the default empty string.

stopStartConnectors

false

When true transport connectors are stopped (client connections are refused), however, the broker will remain running. The transport connectors will be restarted following a successful persistence adapter checkpoint. All exceptions are ignored whilst the transport connectors are stopped. This option ensures that the broker does not need to be manually restarted in the event of a DB restart, for example.

resumeCheckSleepPeriod

5sec

The interval between persistence adapter checkpoints. Typically used in conjunction with stopStartConnectors.

Options in red are available in version 5.5

The default configuration will try to find a specified string in the exception message to determine whether it is a 'no disk space' error. On most platforms (at least those we have tested), you'll find the word 'space' in it. Of course, you can customize this to your platform by using noSpaceMessage property.

Note: as of ActiveMQ 5.11 the JDBCIOExceptionHandler has been deprecated. It has been replaced by the org.apache.activemq.util.LeaseLockerIOExceptionHandler that will work with any persistence adapter that supports pluggable storage lockers whether or not a locker is in use.

Writing your own handler

In case this handler doesn't work for you, you can write your own. For example you might want to change the way how you detect full disk and execute some external command, like df on Linux to be sure.

All you have to do is implement the org.apache.activemq.util.IOExceptionHandler interface then configure the broker to use it:

© 2004-2011 The Apache Software Foundation.
Apache ActiveMQ, ActiveMQ, Apache, the Apache feather logo, and the Apache ActiveMQ project logo are trademarks of The Apache Software Foundation. All other marks mentioned may be trademarks or registered trademarks of their respective owners.
Graphic Design By Hiram