[ENCRYPTION] Adding LUKS-encrypted drive

[Ofnuts]

I'm trying to add a second disk (HDD, first drive is SSD) on a freshly installed Kubuntu 19.10 (where the boot disk is already LUKS encrypted).
I open the Partition Manager and

• select the sda drive (the HDD),
• add a GPT partition table,
• add a primary partition with
  • ext4 file system
  • LUKS encryption option checked
  
  

At some point I'm asked for a passphrase and a mount point, so everything looks fine. I "apply" this and reboot.


On reboot I am not asked the disk passphrase (which didn't bother me too much, I was hoping that the partition manager would also create a keyfile to be able to mount the disk without intervention), but the partition is not mounted, but

• it appears (with the luks type) in the partition manager
• there is an an entry for it in /etc/fstab
• there is no entry for it in /etc/crypttab

In my previous machine (16.04) I had a similar setup but I did it by hand, so I can hopefully redo it, but I'm just hoping that 19.10 can do it in a more automated way, so what is missing? Did I miss an option in the Partition Manager? Or is the LUKS support incomplete?

Edit: some (moderate) progress:

• Delete the partition and recreated it, it appears to have an ext4 filesystem on it (had to ask the PM to rescan to see it).
• FS appears in fstab bit not cryptab
• Reboot takes a lot longer, from approx. 40" to 2'10. systemd-analyze says that system boot tile is normal (17") but user-space is slow (1'55").
• In the booted system the filesystem is not mounted (first checked in a TTY before graphic login, and after graphic login)
• The "Encrypted drive" appears in Dolphin "places".
• If I click on it I get asked the passphrase
• Then I get an error bar in Dolphin saying that the device is already mounted

Is all this normal?