Today the appliance is shipped with ext4 fs with the discard option turned on. We need to check if it can change to xfs and enable the fstrim service instead.
At least on Fedora, fstrim is called by a systemd timer - so no need to do much about it.
As an unforeseen bonus, this reduces the size of the image by 30%.
Even though the fs is now correct with xfs, the fstrim.timer service appears to be disabled by default.
# df -Th
Filesystem Type Size Used Avail Use% Mounted on
/dev/vda1 xfs 6.0G 3.1G 2.9G 52% /
# 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)
Target release should be placed once a package build is known to fix a issue. Since this bug is not modified, the target version has been reset. Please use target milestone to plan a fix for a oVirt release.
Apparently the fix for fstrim.timer service to be enabled by default, hasn't been applied to:
Please check fstrim.timer
System has proper XFS and fstrim.timer is enabled by default.
Needs --grow addition.
--grow is handled by cloud-utils-growpart
The reason seems to be that the addition of swap created a partition after /, and cloud-utils-growpart will not grow it. These are being reversed (swap will be before /)