Description of problem:
On redhat-virtualization-host-4.4.0-20200212.0.el8_2, root partition is defined with discard option in /etc/fstab, and node check shows discard is used, see:

[root@ati-fc-01 ~]# cat /etc/fstab
/dev/rhvh_ati-fc-01/rhvh-4.4.0.12-0.20200212.0+1 / xfs defaults,discard 0 0
UUID=9a760b73-49e8-4495-b3e5-4a8b7748632b /boot                   ext4    defaults        1 2
/dev/mapper/rhvh_ati--fc--01-home /home xfs defaults,discard 0 0
/dev/mapper/rhvh_ati--fc--01-tmp /tmp xfs defaults,discard 0 0
/dev/mapper/rhvh_ati--fc--01-var /var xfs defaults,discard 0 0
/dev/mapper/rhvh_ati--fc--01-var_log /var/log xfs defaults,discard 0 0
/dev/mapper/rhvh_ati--fc--01-var_log_audit /var/log/audit xfs defaults,discard 0 0
/dev/mapper/rhvh_ati--fc--01-swap swap                    swap    defaults        0 0

[root@ati-fc-01 ~]# nodectl check
Status: OK
Bootloader ... OK
  Layer boot entries ... OK
  Valid boot entries ... OK
Mount points ... OK
  Separate /var ... OK
  Discard is used ... OK
Basic storage ... OK
  Initialized VG ... OK
  Initialized Thin Pool ... OK
  Initialized LVs ... OK
Thin storage ... OK
  Checking available space in thinpool ... OK
  Checking thinpool auto-extend ... OK
vdsmd ... OK

All the above information tells user that root partition should be mounted with discard option. But it's not:

[root@ati-fc-01 ~]# mount
/dev/mapper/rhvh_ati--fc--01-rhvh--4.4.0.12--0.20200212.0+1 on / type xfs (rw,relatime,seclabel,attr2,inode64,logbsize=64k,sunit=128,swidth=128,noquota)
/dev/mapper/rhvh_ati--fc--01-tmp on /tmp type xfs (rw,relatime,seclabel,attr2,discard,inode64,logbsize=64k,sunit=128,swidth=128,noquota)
/dev/mapper/rhvh_ati--fc--01-var on /var type xfs (rw,relatime,seclabel,attr2,discard,inode64,logbsize=64k,sunit=128,swidth=128,noquota)
/dev/mapper/rhvh_ati--fc--01-home on /home type xfs (rw,relatime,seclabel,attr2,discard,inode64,logbsize=64k,sunit=128,swidth=128,noquota)
/dev/mapper/rhvh_ati--fc--01-var_crash on /var/crash type xfs (rw,relatime,seclabel,attr2,discard,inode64,logbsize=64k,sunit=128,swidth=128,noquota)
/dev/mapper/36005076300810b3e00000000000002a6p1 on /boot type ext4 (rw,relatime,seclabel)
/dev/mapper/rhvh_ati--fc--01-var_log on /var/log type xfs (rw,relatime,seclabel,attr2,discard,inode64,logbsize=64k,sunit=128,swidth=128,noquota)
/dev/mapper/rhvh_ati--fc--01-var_log_audit on /var/log/audit type xfs (rw,relatime,seclabel,attr2,discard,inode64,logbsize=64k,sunit=128,swidth=128,noquota)


Besides, the fstrim.timer is disabled by default:
[root@ati-fc-01 ~]# systemctl status fstrim.timer
● fstrim.timer - Discard unused blocks once a week
   Loaded: loaded (/usr/lib/systemd/system/fstrim.timer; disabled; vendor preset: disabled)
   Active: inactive (dead)
  Trigger: n/a
     Docs: man:fstrim

We need to decide whether to user fstrim.timer or discard option. 
If use fstrim.timer, it should be enabled by default.
If use discard option, all partitions defined with discard in /etc/fstab should actually be mounted with discard.


Version-Release number of selected component (if applicable):


How reproducible:


Steps to Reproduce:
1.
2.
3.

Actual results:


Expected results:


Additional info: