The NFS Environment
NFS is a distributed file system service that can be used to share resources (files or directories) from one system, typically a server, with other systems on the network. For example, you might want to share third-party applications or source files with users on other systems.
NFS makes the actual physical location of the resource irrelevant to the user. Instead of placing copies of commonly used files on every system, NFS allows you to place one copy on one system's disk and let all other systems access it from the network. Under NFS, remote files are virtually indistinguishable from local ones.
A system becomes an NFS server if it has resources to share on the network. A server keeps a list of currently shared resources and their access restrictions (such as read/write or read-only access).
When you share a resource, you make it available for mounting by remote systems.
You can share a resource in these ways:
By adding an entry to the /etc/dfs/dfstab (distributed file system table) file and rebooting the system
For information on how to share resources, see Chapter 39, Mounting and Unmounting File Systems (Tasks). For a complete description of NFS, see "Managing Network File Systems (Overview)" in System Administration Guide: Resource Management and Network Services.
Automounting or AutoFS
You can mount NFS file system resources by using a client-side service called automounting (or AutoFS), which enables a system to automatically mount and unmount NFS resources whenever you access them. The resource remains mounted as long as you remain in the directory and are using a file. If the resource is not accessed for a certain period of time, it is automatically unmounted.
AutoFS provides the following features:
NFS resources don't need to be mounted when the system boots, which saves booting time.
Users don't need to know the root password to mount and unmount NFS resources.
Network traffic might be reduced, since NFS resources are only mounted when they are in use.
The AutoFS service is initialized by the automount utility, which runs automatically when a system is booted. The automountd daemon runs continuously and is responsible for the mounting and unmounting of the NFS file systems on an as-needed basis. By default, the /home file system is is mounted by the automount daemon.
With AutoFS, you can specify multiple servers to provide the same file system. This way, if one of the servers is down, AutoFS can try to mount from another machine.
For complete information on how to set up and administer AutoFS, see System Administration Guide: IP Services.
Determining a File System's Type
You can determine a file system's type by using the following:
How to Determine a File System's Type
This procedure works whether the file system is mounted or not.
Determine a file system's type by using the grep command.
$ grep mount-point fs-table |
mount-point | Specifies the mount point name of the file system for which you want to know the file system type. For example, the /var directory. |
fs-table | Specifies the absolute path to the file system table in which to search for the file system's type. If the file system is mounted, fs-table should be /etc/mnttab. If the file system isn't mounted, fs-table should be /etc/vfstab. |
Information for the mount point is displayed.
Note - If you have the raw device name of a disk slice, you can use the fstyp command to determine a file system's type (if the disk slice contains a file system). For more information, see fstyp(1M).
Example--Determining a File System's Type
The following example uses the /etc/vfstab file to determine the type of the /export file system.
$ grep /export /etc/vfstab /dev/dsk/c0t3d0s6 /dev/rdsk/c0t3d0s6 /export ufs 2 yes - $ |
The following example uses the /etc/mnttab file to determine the file system type of the currently mounted diskette (which was mounted by vold).
$ grep /floppy /etc/mnttab /vol/dev/diskette0/unnamed_floppy /floppy/unnamed_floppy pcfs rw, nohidden,nofoldcase,dev=16c0009 89103376 $ |