Mounting File Systems

There are several ways to mount file systems. They can be mounted automatically when the system is booted, on demand from the command line, or through the automounter. The automounter provides many advantages to mounting at boot time or mounting from the command line, but many situations require a combination of all three.

How to Mount at Boot Time

If you want to mount file systems at boot time instead of using autofs maps, follow this procedure. Although you must follow this procedure for all local file systems, it is not recommended for remote file systems because it must be completed on every client.

Edit the /etc/vfstab file.

Entries in the /etc/vfstab file have the following syntax:

special  fsckdev  mountp  fstype  fsckpass  mount-at-boot  mntopts

Example of a vfstab entry

You want a client computer to mount the /var/mail directory on the server wasp. You would like it mounted as /var/mail on the client. You want the client to have read-write access. Add the following entry to the client's vfstab file.

wasp:/var/mail - /var/mail nfs - yes rw

NFS servers should not have NFS vfstab entries because of a potential deadlock. The NFS service is started after the entries in /etc/vfstab are checked, so that if you have two servers fail at the same time that are mounting file systems from each other, each system could hang as the systems reboot.

How to Mount From the Command Line

To manually mount a file system during normal operation, run the mount command as superuser:

# mount -F nfs -o ro bee:/export/share/local /mnt

In this case, the /export/share/local file system from the server bee is mounted on read-only /mnt on the local system. Mounting from the command line allows for temporary viewing of the file system. You can unmount the file system with umount or by rebooting the local host.

The version of the mount command released in Solaris 2.6 and in future patches will not warn about invalid options. The command silently ignores any options that cannot be interpreted. Make sure to verify all of the options that were used to prevent unexpected behavior.

How to Verify Options Used With the mount Command

In the Solaris 2.6 release and in any versions of the mount command that were patched after the 2.6 release, no warning is issued for invalid options. The following procedure helps determine whether the options that were supplied either on the command line or through /etc/vfstab were valid.

For this example, assume that the following command has been run:

# mount -F nfs -o ro,vers=2 bee:/export/share/local /mnt

1. Run the nfsstat command to verify the options.

   # nfsstat -m /mnt from bee:/export/share/local Flags: vers=2,proto=tcp,sec=sys,hard,intr,dynamic,acl,rsize=8192,wsize=8192, retrans=5

   Note that the file system from bee has been mounted with the protocol version set to 2. Unfortunately the nfsstat command does not display information about all of the options, but using the nfsstat command is the most accurate way to verify the options.

2. Check the entry in /etc/mnttab.

   The mount command does not allow invalid options to be added to the mount table, so verifying that the options listed in the file match those listed on the command line is a way to check those options not reported by the nfsstat command.

   # grep bee /etc/mnttab bee:/export/share/local /mnt nfs ro,vers=2,dev=2b0005e 859934818

How to Mount With the Automounter

Chapter 5, About Autofs includes the specific instructions for establishing and supporting mounts with the automounter. Without any changes to the generic system, clients should be able to access remote file systems through the /net mount point. To mount the /export/share/local file system from the previous example, all you would need to do is:

% cd /net/bee/export/share/local

Because the automounter allows all users to mount file systems, root access is not required. It also provides for automatic unmounting of file systems, so there is no need to unmount file systems after you are done.