Table of Content
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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 removable filesystems
Terms and Utilities:
/etc/fstab /media/ mount umount
mount
show up mounts FS - mount - cat /dev/mounts or /proc/self/mounts oldhorse@dclab-u1504s:~$ df -h Filesystem Size Used Avail Use% Mounted on udev 230M 0 230M 0% /dev tmpfs 49M 4.8M 44M 10% /run /dev/sda1 98G 1.6G 91G 2% / tmpfs 241M 0 241M 0% /dev/shm tmpfs 5.0M 0 5.0M 0% /run/lock tmpfs 241M 0 241M 0% /sys/fs/cgroup /dev/sdb 20G 55M 19G 1% /myspace tmpfs 49M 0 49M 0% /run/user/1000 oldhorse@dclab-u1504s:~$ cat /etc/fstab # /etc/fstab: static file system information. # # Use 'blkid' to print the universally unique identifier for a # device; this may be used with UUID= as a more robust way to name devices # that works even if disks are added and removed. See fstab(5). # ## / was on /dev/sda1 during installation UUID=bb1f38c8-4af9-4e33-ae34-389cd3496734 / ext4 errors=remount-ro 0 1 # swap was on /dev/sda5 during installation UUID=dbc82d1f-d7eb-4afc-b1de-22f31f9dfd74 none swap sw 0 0 /dev/fd0 /media/floppy0 auto rw,user,noauto,exec,utf8 0 0 /dev/sdb /myspace ext4 defaults,usrjquota=aquota.user,grpjquota=aquota.group,jqfmt=vfsv0 1 3 oldhorse@dclab-u1504s:~$
remount
root@dclab-u1504s:~# mount -o remount,ro /myspace/ root@dclab-u1504s:~# cd /myspace/ root@dclab-u1504s:/myspace# touch ttt touch: cannot touch ‘ttt’: Read-only file system
UUID
Using a label or UUID makesyour system more robust when devices are added or removed.
root@dclab-u1504s:/myspace# blkid /dev/sdb /dev/sdb: UUID="579506c9-2dee-4e12-aeba-8e88c3ea6453" TYPE="ext4" root@dclab-u1504s:/myspace# mkdir uuid root@dclab-u1504s:/myspace# mount UUID="579506c9-2dee-4e12-aeba-8e88c3ea6453" /myspace/uuid root@dclab-u1504s:/myspace# df -h /dev/sdb 20G 55M 19G 1% /myspace/uuid root@dclab-u1504s:/myspace# ll uuid/ total 10564 drwxr-xr-x 3 oldhorse oldhorse 4096 Oct 17 09:43 ./ drwxr-xr-x 4 root root 4096 Oct 18 01:58 ../ -rw------- 1 root root 7168 Oct 17 09:18 aquota.group -rw------- 1 root root 7168 Oct 17 09:18 aquota.user drwx------ 2 oldhorse oldhorse 16384 Oct 4 03:56 lost+found/ -rw-rw-r-- 1 oldhorse oldhorse 1048576 Oct 17 09:43 testfile1 -rw-rw-r-- 1 oldhorse oldhorse 9728000 Oct 17 09:43 testfile2
use softlink to mount
root@dclab-u1504s:/myspace# ls -l $( find /dev -lname "*sdb*") lrwxrwxrwx 1 root root 6 Oct 18 01:43 /dev/block/8:16 -> ../sdb lrwxrwxrwx 1 root root 9 Oct 18 01:43 /dev/disk/by-path/pci-0000:00:10.0-scsi-0:0:1:0 -> ../../sdb lrwxrwxrwx 1 root root 9 Oct 18 01:43 /dev/disk/by-uuid/579506c9-2dee-4e12-aeba-8e88c3ea6453 -> ../../sdb root@dclab-u1504s:/# mount /dev/disk/by-path/pci-0000:00:10.0-scsi-0:0:1:0 /myspace root@dclab-u1504s:/# df -h|grep sdb /dev/sdb 20G 55M 19G 1% /myspace
umount
umount <dev|mountpoint>
check opening file on mounted FS
root@dclab-u1504s:/# cd /myspace/ root@dclab-u1504s:/myspace# ll total 10564 drwxr-xr-x 3 oldhorse oldhorse 4096 Oct 17 09:43 ./ drwxr-xr-x 23 root root 4096 Oct 17 07:35 ../ -rw------- 1 root root 7168 Oct 17 09:18 aquota.group -rw------- 1 root root 7168 Oct 17 09:18 aquota.user drwx------ 2 oldhorse oldhorse 16384 Oct 4 03:56 lost+found/ -rw-rw-r-- 1 oldhorse oldhorse 1048576 Oct 17 09:43 testfile1 -rw-rw-r-- 1 oldhorse oldhorse 9728000 Oct 17 09:43 testfile2 root@dclab-u1504s:/myspace# lsof -w /myspace/ COMMAND PID USER FD TYPE DEVICE SIZE/OFF NODE NAME bash 873 root cwd DIR 8,16 4096 2 /myspace lsof 1060 root cwd DIR 8,16 4096 2 /myspace lsof 1061 root cwd DIR 8,16 4096 2 /myspace root@dclab-u1504s:/myspace# fuser -m /myspace/ /myspace: 873c root@dclab-u1504s:/myspace# ps -ef|grep 873 root 873 872 0 01:55 pts/0 00:00:00 -su root 1075 873 0 02:09 pts/0 00:00:00 ps -ef root 1076 873 0 02:09 pts/0 00:00:00 grep --color=auto 873
lazy umount
root@dclab-u1504s:/myspace# umount /myspace
umount: /myspace: target is busy
(In some cases useful info about processes that
use the device is found by lsof(8) or fuser(1).)
root@dclab-u1504s:/myspace# umount -l /myspace
root@dclab-u1504s:/myspace# df -h|grep myspace
root@dclab-u1504s:/myspace#
root@dclab-u1504s:/myspace# ll
total 10564
drwxr-xr-x 3 oldhorse oldhorse 4096 Oct 17 09:43 ./
drwxr-xr-x 3 oldhorse oldhorse 4096 Oct 17 09:43 ../
-rw------- 1 root root 7168 Oct 17 09:18 aquota.group
-rw------- 1 root root 7168 Oct 17 09:18 aquota.user
drwx------ 2 oldhorse oldhorse 16384 Oct 4 03:56 lost+found/
-rw-rw-r-- 1 oldhorse oldhorse 1048576 Oct 17 09:43 testfile1
-rw-rw-r-- 1 oldhorse oldhorse 9728000 Oct 17 09:43 testfile2
root@dclab-u1504s:/myspace# umount -f /myspace
umount: /myspace: target is busy
(In some cases useful info about processes that
use the device is found by lsof(8) or fuser(1).)
CD/DVD mount
root@dclab-u1504s:/myspace# ls -l /dev|grep sr lrwxrwxrwx 1 root root 3 Oct 18 01:43 cdrom -> sr1 lrwxrwxrwx 1 root root 3 Oct 18 01:43 cdrw -> sr1 lrwxrwxrwx 1 root root 3 Oct 18 01:43 dvd -> sr1 brw-rw---- 1 root cdrom 11, 0 Oct 18 01:43 sr0 brw-rw---- 1 root cdrom 11, 1 Oct 18 01:43 sr1 root@dclab-u1504s:/myspace# ll /media/ drwxr-xr-x 2 root root 4096 Sep 20 06:26 cdrom/ root@dclab-u1504s:/myspace# ll /media/cdrom/ total 8 drwxr-xr-x 2 root root 4096 Sep 20 06:26 ./ drwxr-xr-x 4 root root 4096 Sep 20 06:26 ../ root@dclab-u1504s:/myspace# mount /dev/sr0 /media/cdrom/ mount: /dev/sr0 is write-protected, mounting read-only root@dclab-u1504s:/myspace# df -h /dev/sr0 31M 31M 0 100% /media/cdrom root@dclab-u1504s:/myspace# mount |grep sr0 /dev/sr0 on /media/cdrom type iso9660 (ro,relatime) root@dclab-u1504s:/myspace#
swap
root@dclab-u1504s:/myspace# swapon -s Filename Type Size Used Priority /dev/sda5 partition 1045500 0 -1 root@dclab-u1504s:/myspace# fdisk -l /dev/sda Disk /dev/sda: 100 GiB, 107374182400 bytes, 209715200 sectors Units: sectors of 1 * 512 = 512 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disklabel type: dos Disk identifier: 0x1d4280cc Device Boot Start End Sectors Size Id Type /dev/sda1 * 2048 207620095 207618048 99G 83 Linux /dev/sda2 207622142 209713151 2091010 1021M 5 Extended /dev/sda5 207622144 209713151 2091008 1021M 82 Linux swap / Solaris
Quiz questions
1. Write the full command to mount the first partition of the third scsi disk on the /mnt directory 2. How would you allow a non root user to mount a cdrom on /mnt/cdrom? 3. How does one prevent a filesystem from being mounted at bootup? 4. Who can use the umount command? Answers to quiz questions 1. mount /dev/sdc1 /mnt 2. Create an entry in /etc/fstab with “user” and “noauto” in the options column. 3. Add “noauto” in the options column in /etc/fstab. 4. Only root, unless the filesystem was mounted by the user and the options column in /etc/fstab includes “user”.