Since the Oracle OCFS2 file system caters for Linux and not for Solaris, SPARC server pools are unable to use this file system to implement clustering functionality. Therefore, clustering for SPARC server pools cannot be implemented on physical disks and are limited to using NFS storage to host the cluster file system. Clustering for SPARC server pools relies on an additional package, which must be installed in the control domain for each Oracle VM Server in the server pool. This package contains a distributed lock manager (DLM) that is used to to facilitate the cluster. Installation of this package is described in more detail in Installing DLM for SPARC Server Pool Clusters in the Oracle VM Installation and Upgrade Guide.
The DLM package used to achieve clustering for SPARC server pools is a port of the tools that are used within OCFS2 on Linux, but exclude the actual OCFS2 file system itself. The DLM package includes:
A disk heartbeat to detect live servers.
A network heartbeat for communication between the nodes.
A Distributed Lock Manager (DLM) which allows shared disk resources to be locked and released by the servers in the cluster.
The only major difference between clustering on SPARC and on x86 is that there are limitations to the types of shared disks that SPARC infrastructure can use to host the cluster file system. Without OCFS2, clustering depends on a file system that is already built to facilitate shared access and this is why only NFS is supported for this purpose. Unlike in x86 environments, when NFS is used to host a SPARC server pool file system, an OCFS2 disk image is not created on the NFS share. Instead, the cluster data is simply stored directly on the NFS file system itself.
With this information in mind, the description provided in Section 6.8.1, “Clustering for x86 Server Pools” largely applies equally to clustering on SPARC, although the implementation does not use OCFS2.
A final point to bear in mind is that clustering for SPARC server pools is only supported where a single control domain has been configured on all of the Oracle VM Servers in the server pool. If you have decided to make use of multiple service domains, you must configure an unclustered server pool. See Section 6.9, “Unclustered Server Pools” for more information.