Running Linux, 5th Edition - Matthias Kalle Dalheimer [188]
The second value is optional and specifies flags to be used for the mount operation. These are equivalent to those for the mount command itself, with the exception that the type is specified with the option -fstype=instead of -t.
Finally, the third value specifies the partition or device to be mounted. In our case, we specify the first SCSI CD-ROM drive and the first floppy drive, respectively. The colon in front of the entry is mandatory; it separates the host part from the device/directory part, just as with mount. Because those two devices are on a local machine, there is nothing to the left of the colon. If we wanted to automount the directory sources from the NFS server sourcemaster, we would specify something like the following:
sources -fstype=nfs,soft sourcemaster:/sources
Please notice that the /etc/auto.misc file must not be executable; when in doubt, issue the following command:
tigger# chmod a-x /etc/auto.misc
After editing the configuration files to reflect your system, you can start the automount daemon by issuing the following command (replace the path with the path that suits your system):
tigger# /etc/init.d/autofs start
Because this command is very taciturn, you should check whether the automounter has really started. One way to do this is to issue:
tigger# /etc/init.d/autofs status
but it is difficult to determine from the output whether the automounter is really running. Your best bet, therefore, is to check whether the automount process exists:
tigger# ps aux | grep automount
If this command shows the automount process, everything should be all right. If it doesn't, you need to check your configuration files again. It could also be the case that the necessary kernel support is not available: either the automount support is not in your kernel, or you have compiled it as a module but not installed this module. If the latter is the case, you can fix the problem by issuing
tigger# modprobe autofs
If that doesn't work, you need to use:
tigger# modprobe autofs4
instead.[*] When your automounter works to your satisfaction, you might want to put the modprobe call as well as the autofs call in one of your system's startup configuration files, such as /etc/rc.local, /etc/init.d/boot.local, or whatever your distribution uses.
If everything is set up correctly, all you need to do is access some directory below the mount point, and the automounter will mount the appropriate device or partition for you. For example, if you type
tigger$ ls /automount/cd
the automounter will automatically mount the CD-ROM so that ls can list its contents. The only difference between normal and automounting is that with automounting you will notice a slight delay before the output comes.
To conserve resources, the automounter unmounts a partition or device if it has not been accessed for a certain amount of time (the default is five minutes).
The automounter supports a number of advanced options; for example, you do not need to read the map table from a file but can also access system databases or even have the automounter run a program and use this program's output as the mapping data. See the manpages for autofs(5) and automount(8) for further details.
Creating Filesystems
You can create a filesystem using the mkfs command. Creating a filesystem is analogous to formatting a partition or floppy, allowing it to store files.
Each filesystem type has its own mkfs command associated with it—for example, MS-DOS filesystems may be created using mkfs.msdos, Third Extended filesystems using mkfs.ext3, and so on. The program mkfs itself is a frontend that creates a filesystem of any type by executing the appropriate version of mkfs for that type.
When you installed Linux, you may have created filesystems by hand using a command such as mke2fs, which, despite the name, can create both ext2 and ext3 filesystems. (If not, the installation software created the filesystems