[CentOS] C7 and swap

Hi list, today I've noticed a strange behaviour during system startup. This is a workstation. During mounting swap, system waits at least 90 seconds before continue. When system is loaded swap seems to be not mounted. Running free -h , it reports for swap 0 total and 0 for other values.

Always during booting process, when it waits for swap mounting, it reports the uuid of swap partion. This uuid is on fstab but it is not listed under /dev/disk/by-uuid.

Changing fstab with /dev/device all works good.

Why I can't find swap partition in /dev/disk/by-uuid?

Thanks in advance.

Alessandro.