Making mounts persist

When issuing a mount command at the command line, the mount will only persist until the machine is rebooted. If we always want that particular mount to persist we can put an entry in /etc/fstab.

• See /etc/fstab
• Here is an example entry
  • /dev/sda6 /home/joe/op auto defaults 0 0

Fstab Fields - Field 1

• Device name or block id (next slide)

  • local or remote

• Examples:

  • /dev/sda1
  • UUID=4e45f5c1-472e-4983-94f2-ca13038c3d96

UUID

Ubuntu now uses UUID to identify partitions. To find out what the UUID is for a particular device we can use:

• sudo blkid

This is the recommended method, as device names are often a coincidence of hardware detection order, and can change when other disks are added or removed. Say that that you plugged another disk into your computer and booted up. It probably won’t happen, but it is possible that the new disk might be identified as /dev/sda, causing the system to look for the contents of /boot on the first partition of that disk.

Fstab Fields - Fields 2

• Field 2 is the mount point

  • where should it show up in my fs tree?
  • You generally create the mount point with mkdir command
  • for swap, this should be none

• Examples:

  • /home/bob/mnt
  • /mounts

Fstab Fields - Field 3

• Type of filesystem to be mounted
• Types: ext4, xfs, btrfs, f2fs, vfat, ntfs, hfs‐ plus, tmpfs, sysfs, proc, iso9660, udf, squashfs, nfs, cifs, and many more.

Fstab Fields - Field 4

• Mount options
  • defaults = use default options: rw, suid, dev, exec, auto, nouser, and async.
  • noauto = do not mount when “mount -a” is given (e.g., at boot time)
  • user = allow a user to mount
  • owner = allow device owner to mount

Fstab Fields - Field 5-6

• 5 = Used to determine which fs need to be dumped (not used anymore)
• 6 = Order of fsck at boot time (root fs is first (1), others should have (2))
  • used to be more important, not so much now