Oracle® Solaris Cluster Software Installation Guide

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Updated: September 2014, E39580-02

Planning Cluster File Systems

For information about the purpose and function of cluster file systems, see Cluster File Systems in Oracle Solaris Cluster Concepts Guide .

Note -  You can alternatively configure highly available local file systems. This can provide better performance to support a data service with high I/O, or to permit use of certain file system features that are not supported in a cluster file system. For more information, see Enabling Highly Available Local File Systems in Oracle Solaris Cluster Data Services Planning and Administration Guide .

Consider the following points when you plan cluster file systems:

  • Quotas – Quotas are not supported on cluster file systems. However, quotas are supported on highly available local file systems.

  • Zone clusters – You cannot configure cluster file systems that use UFS for use in a zone cluster. Use highly available local file systems instead. You can use a Sun QFS shared file system in a zone cluster only to support Oracle RAC.

  • Loopback file system (LOFS) – During cluster creation, LOFS is enabled by default. You must manually disable LOFS on each cluster node if the cluster meets both of the following conditions:

    • HA for NFS (HA for NFS) is configured on a highly available local file system.

    • The automountd daemon is running.

    If the cluster meets both of these conditions, you must disable LOFS to avoid switchover problems or other failures. If the cluster meets only one of these conditions, you can safely enable LOFS.

    If you require both LOFS and the automountd daemon to be enabled, exclude from the automounter map all files that are part of the highly available local file system that is exported by HA for NFS.

  • Process accounting log files – Do not locate process accounting log files on a cluster file system or on a highly available local file system. A switchover would be blocked by writes to the log file, which would cause the node to hang. Use only a local file system to contain process accounting log files.

  • Communication endpoints – The cluster file system does not support any of the file system features of Oracle Solaris software by which one would put a communication endpoint in the file system namespace. Therefore, do not attempt to use the fattach command from any node other than the local node.

    • Although you can create a UNIX domain socket whose name is a path name into the cluster file system, the socket would not survive a node failover.

    • Any FIFOs or named pipes that you create on a cluster file system would not be globally accessible.

  • Device special files – Neither block special files nor character special files are supported in a cluster file system. To specify a path name to a device node in a cluster file system, create a symbolic link to the device name in the /dev directory. Do not use the mknod command for this purpose.

  • atime – Cluster file systems do not maintain atime.

  • ctime – When a file on a cluster file system is accessed, the update of the file's ctime might be delayed.

  • Installing applications - If you want the binaries of a highly available application to reside on a cluster file system, wait to install the application until after the cluster file system is configured.