1. Installing and Configuring an Oracle Solaris Cluster 4.4 Environment
  2. Planning the Oracle Solaris Cluster Configuration
  3. Planning the Oracle Solaris Cluster Environment
  4. NFS Guidelines

NFS Guidelines

Consider the following points when you plan the use of Network File System (NFS) in an Oracle Solaris Cluster configuration:

  • NFS client – A cluster node cannot be an NFS client of an Oracle Solaris Cluster HA for NFS exported file system when the underlying file system is UFS. However, you can perform this type of cross mounting when the underlying file system is ZFS.

    This cross-mounting restriction applies to a client node and an NFS server in the same cluster. Instead, use the cluster file system to share files between cluster nodes.

    A cluster node can be an NFS client of a qualified NAS device.

  • HA-NFS as cluster-shared storage – You cannot use HA-NFS as a cluster-shared storage method for running HA data services on cluster nodes that mount the exported NFS file systems. You cannot use this method because there is no mechanism to release NFS file locks and perform NFS fencing against a possibly faulted NFS client cluster node. As a result, the data service might not be able to start on a new node.

    This restriction applies when the data services are on the same or a different cluster than the HA-NFS cluster.

    This restriction only applies when the HA-NFS-exported file systems are used as cluster-shared storage. So, you can use this configuration for user home directories, offline copy of data, and so on.

    If you must use NFS as a shared-storage method for HA data services, you must use a qualified NAS device.

  • NFSv3 protocol – If you are mounting file systems on the cluster nodes from external NFS servers, such as NAS filers, and you are using the NFSv3 protocol, you cannot run NFS client mounts and the HA for NFS data service on the same cluster node. If you do, certain HA for NFS data-service activities might cause the NFS daemons to stop and restart, interrupting NFS services. However, you can safely run the HA for NFS data service if you use the NFSv4 protocol to mount external NFS file systems on the cluster nodes.

  • Locking – Applications that run locally on the cluster must not lock files on a file system that is exported through NFS. Otherwise, local blocking (for example, flock or fcntl) might interfere with the ability to restart the lock manager ( lockd). During restart, a blocked local process might be granted a lock which might be intended to be reclaimed by a remote client. This situation would cause unpredictable behavior.

  • NFS security features – Oracle Solaris Cluster software does not support the following options of the share_nfs(8) command:

    • secure

    • sec=dh

    However, Oracle Solaris Cluster software does support the following security features for NFS:

    • The use of secure ports for NFS. You enable secure ports for NFS by adding the entry set nfssrv:nfs_portmon=1 to the /etc/system file on cluster nodes.

    • The use of Kerberos with NFS.

  • Fencing – Zone clusters support fencing for all supported NAS devices, shared disks, and storage arrays.