Choosing Mount Options for UFS Cluster File Systems

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This section describes requirements and restrictions for mount options of the following types of UFS cluster file systems:

Note - You can alternatively configure this and other types of file systems as highly available local file systems. For more information, see Enabling Highly Available Local File Systems in Oracle Solaris Cluster Data Services Planning and Administration Guide .

Follow the guidelines in the following list of mount options in the following list of mount options to determine what mount options to use when you create your UFS cluster file systems.

global

Required. This option makes the file system globally visible to all nodes in the cluster.

logging

Required. This option enables logging.

forcedirectio

Conditional. This option is required only for cluster file systems that will host Oracle RAC RDBMS data files, log files, and control files.

onerror=panic

Required. You do not have to explicitly specify the onerror=panic mount option in the /etc/vfstab file. This mount option is already the default value if no other onerror mount option is specified.

Note - Only the onerror=panic mount option is supported by Oracle Solaris Cluster software. Do not use the onerror=umount or onerror=lock mount options. These mount options are not supported on cluster file systems for the following reasons:

Use of the onerror=umount or onerror=lock mount option might cause the cluster file system to lock or become inaccessible. This condition might occur if the cluster file system experiences file corruption.
The onerror=umount or onerror=lock mount option might cause the cluster file system to become unmountable. This condition might thereby cause applications that use the cluster file system to hang or prevent the applications from being killed.

A node might require rebooting to recover from these states.

syncdir

Optional. If you specify syncdir, you are guaranteed POSIX-compliant file system behavior for the write() system call. If a write() succeeds, then this mount option ensures that sufficient space is on the disk.

If you do not specify syncdir, the same behavior occurs that is seen with UFS file systems. When you do not specify syncdir, performance of writes that allocate disk blocks, such as when appending data to a file, can significantly improve. However, in some cases, without syncdir you would not discover an out-of-space condition (ENOSPC) until you close a file.

You see ENOSPC on close only during a very short time after a failover. With syncdir, as with POSIX behavior, the out-of-space condition would be discovered before the close.

See the mount_ufs (1M) man page for more information about UFS mount options.

UFS Cluster File Systems

Mount Option	Usage	Description
`global`	Required	This option makes the file system globally visible to all nodes in the cluster.
`logging`	Required	This option enables logging.
`forcedirectio`	Conditional	This option is required only for cluster file systems that will host Oracle RAC RDBMS data files, log files, and control files.
`onerror=panic`	Required	You do not have to explicitly specify the `onerror=panic` mount option in the `/etc/vfstab` file. This mount option is already the default value if no other `onerror` mount option is specified. Note - Only the `onerror=panic` mount option is supported by Oracle Solaris Cluster software. Do not use the `onerror=umount` or `onerror=lock` mount options. These mount options are not supported on cluster file systems for the following reasons: Use of the `onerror=umount` or `onerror=lock` mount option might cause the cluster file system to lock or become inaccessible. This condition might occur if the cluster file system experiences file corruption. The `onerror=umount` or `onerror=lock` mount option might cause the cluster file system to become unmountable. This condition might thereby cause applications that use the cluster file system to hang or prevent the applications from being killed. A node might require rebooting to recover from these states.
`syncdir`	Optional	If you specify `syncdir`, you are guaranteed POSIX-compliant file system behavior for the `write()` system call. If a `write()` succeeds, then this mount option ensures that sufficient space is on the disk. If you do not specify `syncdir`, the same behavior occurs that is seen with UFS file systems. When you do not specify `syncdir`, performance of writes that allocate disk blocks, such as when appending data to a file, can significantly improve. However, in some cases, without `syncdir` you would not discover an out-of-space condition (`ENOSPC`) until you close a file. You see `ENOSPC` on close only during a very short time after a failover. With `syncdir`, as with POSIX behavior, the out-of-space condition would be discovered before the close.

See the mount_ufs (1M) man page for more information about UFS mount options.