The Network File System (NFS) is a client-server service that lets users view, store, and update files on a remote computer as though they were on their own local computer.
# vi /etc/dfs/dfstab ==> to share local resources
# share [-F fstype] [ -o options] [-d "<text>"] <pathname> [resource]
# .e.g,
# share -F nfs -o rw=engineering -d "home dirs" /export/home2
share -F nfs -o ro -d "Shared data files" /usr/local/data
share -F nfs -o rw,root=sys-01 -d "Database files" /rdbms_files
Note – If svc:/network/nfs/server service does not find any share commands in the /etc/dfs/dfstab file, it does not start the NFS server daemons.
# cat /etc/dfs/sharetab ==> to view local resources currently shared
# cat /etc/dfs/fstypes ==> to view a system’s distributed file
system types
# cat /etc/rmtab ==> to view file systems remotely mounted by
NFS clients
sys-03:/usr/local/data
sys-02:/export/config
#ys-02:/export/config
Managing the NFS Server Daemons
# svcadm enable svc:/network/nfs/server ==> to start the NFS server
daemons
Note – If the svc:/network/nfs/server service does not find any share commands in the /etc/dfs/dfstab file, it does not start the NFS server daemons.
# svcadm disable svc:/network/nfs/server ==> to stop the NFS server
daemons
NFS Server Commands
share Makes a local directory on an NFS server available for mounting. It also displays the contents of the /etc/dfs/sharetab file.
unshare Makes a previously available directory unavailable for client side mount operations.
shareall Reads and executes share statements in the /etc/dfs/dfstab file.
unshareall Makes previously shared resources unavailable.
dfshares Lists available shared resources from a remote or local NFS server.
dfmounts Displays a list of NFS server directories that are currently mounted.
Configuringthe NFS Server for Sharing Resources
syntax: share [ -F nfs ] [ -o options ] [ -d description ] [ pathname ]
# share -o ro /usr/local/data ==> to share a file resource
# share -F nfs -o ro directory ==> restricts access to NFS-mounted
resources to read-only access
# share -F nfs -o ro,rw=client1 directory ==> Restricts access to NFS
mounted resources to read-only
access; however, the NFS server
accepts read & write requests
from client named client1.
# share -F nfs -o root=client2 directory ==> Allows the root user on the
client named client2 to have
superuser access to the NFS
mounted resources
This command shares the directory to the four named hosts only. The hosts, client1 and client2, have read-only access. The hosts client3 and client4 have read-write access. The root user from host client4 has root privilege access to the shared directory and its contents.
# share -F nfs -o ro=client1:client2,rw=client3:client4,root=client4 directory
# share ==> to display a list of all currently shared file resources
Making File Resources Unavailable for Mounting
syntax: unshare [ -F nfs ] pathname
# unshare /usr/local/data ==> to make the /usr/local/data directory
unavailable for client-side mount
operations
Sharing and Unsharing All NFS Resources
shareall [ -F nfs ]
unshareall [ -F nfs ]
# shareall ==> to share all resources listed in /etc/dfs/dfstab file
# unshareall ==> to unshare currently shared file resources listed in
/etc/dfs/sharetab file
Displaying Currently Shared NFS Resources
dfshares [ -F nfs ] [ host ]
# dfshares ==> to display the resources currently being shared by the
local server
# dfshares sys-01 ==> to display resources shared by another server
# share ==> to display a list of all currently shared file resources
Displaying NFS Mounted Resources
dfmounts [ -F nfs ] [ server ]
# dfmounts ==> to display remotely mounted NFS resource information
RESOURCE SERVER PATHNAME CLIENTS
- sys-02 /usr/local/data sys-03
Managing the NFS Client
Managing the NFS Client Daemons
# svcadm restart svc:/network/nfs/client ==> to start NFS client
daemons
NFS Client Commands
# dfshares servername
# mount
# umount
# mountall
# umountall
Configuring the NFS Client for Mounting Resources
# dfshares sys-01 ==> to list the resources of an NFS server
Mounting a remote file resource
mount [ -F nfs ] [ -o options ] server:pathname mount_point
# mount sys-02:/rdbms_files /mnt ==> to mount a remote file resource
# mount -o ro sys-45,sys-43,sys-41:/multi_homed_data /remote_shared_data
In the above example, if sys-45 server is unavailable, the request passes to
the next server on the list, sys-43, and then to the sys-41 server. This process works if the resource mounted from all of the servers is the same.
Unmounting a remote file resource
umount server:pathname or mount_point
# umount /rdbms_files ==> to unmount a remote file resource
Mounting & Unmounting remote file resources only (resources listed in the
/etc/vfstab file with a mount at boot value of yes)
mountall -r [ -F nfs ]
umountall -r [ -F nfs ]
# mountall -r ==> to mount all remote file resources only
# umountall -r ==> to unmount all remote file resuources only
Note – Use the -F FSType with the mountall and umountall commands to specify FSType as the file system type. You do not have to specify the -F nfs option, because NFS is listed as the default remote file system type.
Mounting Remote Resources at Boot Time
Enter appropriate entries in the client’s /etc/vfstab file to mount remote file resources at boot time
# vi /etc/vfstab
#device device mount FS fsck mount mount
#to mount to fsck point type pass at boot options
#
sys-02:/usr/local/data - /usr/remote_data nfs - yes soft,bg
bg|fg During an NFS mount request, if the first mount attempt fails, retry in the background or foreground.
The default is to retry in the foreground.
soft|hard When the number of retransmissions has reached the number specified in the retrans=n option, a file system mounted with the soft option reports an error on the request, and stops trying. A file system mounted with the hard option prints a warning message and continues to try to process the request.
The default is a hard mount.
Although the soft option and the bg option are not the default settings, combining them usually results in the fastest client boot when NFS mounting problems occur.
Enabling NFS Server Logging
Note – Server logging is not supported in NFS version 4.
Create tag entries for each of the server’s shared resources.
The global tag defines the default values.
# cat /etc/nfs/nfslog.conf ==> to configure NFS log paths
# NFS server log configuration file.
#
# <tag> [ defaultdir=<dir_path> ] \
# [ log=<logfile_path> ] [ fhtable=<table_path> ] \
# [ buffer=<bufferfile_path> ] [ logformat=basic|extended ]
#
global defaultdir=/var/nfs \
log=nfslog fhtable=fhtable buffer=nfslog_workbuffer
To easily identify the log files for different shared resources, place them in
separate directories. For example:
# cat /etc/nfs/nfslog.conf
# NFS server log configuration file.
#
global defaultdir=/var/nfs \
log=nfslog fhtable=fhtable buffer=nfslog_workbuffer
public defaultdir=/var/nfs/public \
log=nfslog fhtable=fhtable buffer=nfslog_workbuffer
Note – Create /var/nfs/public directory before starting NFS server logging.
Initiating NFS Logging
1. Become superuser.
2. Optional: Change the file system configuration settings.
In the /etc/nfs/nfslog.conf file, either:
Edit the default settings for all file systems by changing the data
corresponding to the global tag.
Add a new tag for the specific file system.
If you do not need these changes, do not edit this file.
3. Edit the /etc/dfs/dfstab file to add an entry for file systems for which
you want to enable NFS server logging.
Either:
Use log option without specifying a tag - to use the global tag as
default.
Specify a tag - with the log=tag option
share -F nfs -olog /export/sys44_data
share -F nfs -olog=public /export/sys44_data
4. Check that the NFS service is running on the server, if not start it.
# svcadm enable svc:/network/nfs/server
5. Run the share command to verify that the correct options are listed.
# share
6. If you add additional entries to /etc/dfs/dfstab file, share the file
system by rebooting the system or entering the shareall command.
# shareall
