3.2.7. HornetQ Changes
3.2.7.1. About HornetQ and NFS
In most cases, NFS is not an appropriate method of storing JMS data for use with HornetQ, when using NIO as the journal type, due to the way the synchronous locking mechanism works. However, NFS can be used in certain circumstances, only on Red Hat Enterprise Linux servers. This is due to the NFS implementation used by Red Hat Enterprise Linux.
The Red Hat Enterprise Linux NFS implementation supports both direct I/O (opening files with the O_DIRECT flag set), and kernel based asynchronous I/O. With both of these features present, it is possible to use NFS as a shared storage option, under strict configuration rules:
- The Red Hat Enterprise Linux NFS client cache must be disabled.
Important
The server log should be checked after JBoss EAP 6 is started, to ensure that the native library successfully loaded, and that the ASYNCIO journal type is being used. If the native library fails to load, HornetQ will gracefully fail to the NIO journal type, and this will be stated in the server log.
Important
The native library that implements asynchronous I/O requires that
libaio is installed on the Red Hat Enterprise Linux system where JBoss EAP 6 is running.
