LPI Linux Certification/Control Mounting And Unmounting Of Filesystems

Detailed Objectives (LPIC-1 Version 5.0) Weight: 3 Description: Candidates should be able to configure the mounting of a filesystem. Key Knowledge Areas: Manually mount and unmount filesystems. Configure filesystem mounting on bootup. Configure user mountable removeable filesystems. Use of labels and UUIDs for identifying and mounting file systems. Awareness of systemd mount units. The following is a partial list of the used files, terms and utilities: /etc/fstab /media/ mount umount blkid lsblk Attach a filesystem The mount command serves to attach the file system found on some device to the big file tree. mount [options] mount [options] [-t vfstype] [-o options] device dir If the device or directory is listed in /etc/fstab you can use the following: mount [options] [-o options [,...]] device | dir Normally only root has the privilege to mount devices unless it is specified in the /etc/fstab file. Examples: # Print all the mounted filesystems (/etc/mtab). mount # Mount devices or dirs listed in /etc/fstab. mount -a # Mount /dev/hdc partition in read only mode without updating /etc/mtab. mount -n -o ro /dev/hdc /mnt # Allow a user to mount the CDROM if the following line is in /etc/fstab: # /dev/cdrom /media/cdrom iso9660 ro,user,noauto,unhide mount /media/cdrom mount /dev/cdrom # Sync in realtime mount -o sync /dev/sdb1 /mnt/usb Detach a filesystem To detach a filesystem from the file tree, use umount. umount [options] umount [options] [-o options [,...]] device | dir A busy filesystem cannot be unmounted. Open files Working directory of a process. Examples: umount -a # Unmount devices or dirs listed in /etc/fstab. umount /mnt # Unmount the filesystem attached to /mnt. umount /media/cdrom # Allow a user to unmount the CDROM if the following line is in /etc/fstab: /dev/cdrom /media/cdrom iso9660 ro,user,noauto,unhide File system information The file /etc/fstab contains all the file systems and related information that will be used when doing a mount -a. (Boot time) The file /etc/mtab is maintained by the kernel and keeps track on what is or isn't mounted. The /etc/fstab format is: #Device Mount point Fs type Options 1 2 /dev/hda3 / reiserfs defaults 1 2 /dev/hda1 /boot ext2 defaults 1 2 /dev/cdrom /media/cdrom auto ro,noauto,user,exec 0 0 usbdevfs /proc/bus/usb usbdevfs noauto 0 0 /dev/hda2 swap swap pri=42 0 0 Common options: ro: read only noauto: Don't mount automatically exec: Can execute binary on the filesystem suid: Allow to setuser bit user: Allow a user to mount/unmount it unhide: hidden file visible async: All operations will be done asynchronously default: rw, suid, dev, exec, auto, nouser, and async Exercises Exercises results Create a line in /etc/fstab that allows any user to access the floppy disk. Check that you can mount the floppy and can create a file with touch. Do the following manipulation: Create a ext2 file system on the floppy. Mount the floppy. Copy all the files /etc/*.conf into the floppy. Unmount it. What's happening? Mount it back and check that all the files are there. Issue the following command: Tar cvf /dev/fd0 /etc/*.conf Try to mount it back. What's happening? Use tar to view the contents of the floppy. Linux