The UUID in fstab is used as the unique identifier of the hard disk for mounting and other operations.

In ubuntu, we found that the system uses UUID to uniquely represent the hard disk partition, for example:

#/Dev/sda1
# UUID = 45f8-9147/Media/sda1 vfat defaults, utf8, umask = 000 0 1
/Dev/sda1/Media/sda1 vfat defaults, utf8, umask = 000 0 1
#/Dev/sda5
UUID = 5668d81168d7edad/Media/sda6 ntfs-3g ults, NLS = utf8, umask = 000 0 1

One advantage of using/dev/sda5 to directly reference a partition is that when a new partition is added to the hard disk or the partition sequence changes, still ensure that the system loads partitions to the correct loading point.

This is especially important for swap partitions. If the order of Hard Disk Partitions is changed, and fstab makes a response to swap partition numbers, will it use other partitions as swap? The result is terrible. The data in this partition may not be guaranteed.

The UUID list in/dev/Disk/UUID is actually some soft link files. The system can generate a unique encoding for each partition and increase the system stability.