Nothing since 2015.. Sad..

And change storage for customers easely, if they need more…

I want to achieve "a better use of the capacity from the storage" by setting multiple default virtualhost locations. ie:

HTTPD_VHOSTS_D as /var/www/vhosts/ in /etc/psa/psa.conf

But several ones,

/mnt/www/vhosts2
/var/www/vhosts
/home/www/vhosts3

Sorry, but this is critical. In cloud solutions you can manage the disk size, but baremetals have restrictions. cpanel fofer /home, /home2, /home3 etc solution. I know I can manually bind certain directories to other storages, but non sysadmin users can not move certain vhosts to another storage without know command line stuffs. and even cloud has restriction per volume, so sometimes you need to add more volumes.

This!

definitely this feature is a must have for long term.

It'll be useful to have multiple vhosts, mailnames, dumps directories at the same time.
When the server gets out of disk space it'll be great to be able to just add a new disk and use its disk space without changing the location of the original directories.

We're studying for some customer/subscriptions that consume a lot of GB of disk space, to have their own /var/www/vhosts/client as a new disk mount.

Need this feature for scaling server.

this is a very important feature. it will helps to scale the bare metal server and at the same time we can provide low storage performance to certain customers and high storage performance for premium users.

Our dedicated server has multiple disks (SSD and HDD), it's very necessary feature for us.

That's will be indeed really useful for added volume like we can do on DigitalOcean. The competition is much more advanced than us on this topic and this is really used by the expert community when we see the forums. So, for us we still need to mount the disk (additional volume) by changing the main filesystem volume by extending it with the additional volume, which is really critical for non-expert people.
I will not say "if people don't vote for this means our community doesn't need it", because before to choose your solution I was looking for this feature and all forums and people simply redirect us to the competition as this like this since years now.
So, people will not come here to ask for this feature, most of them will simply move to another service.
I finally chose Plesk because of other features, but definitely this feature is a must have for long term.

Cpanel does have a feature where if you mount your additional disk under /home2, it will start saving accounts there if the main disk (/home) gets full.

The idea is: Use 2 Vhosts or more with different drives with Plesk.

Please allow us to add a vhost alias domain that uses a custom chosen folder (from a completely other domain) but can be attached to another subscription/customer.

This would enable us to allow mail and dns configuration by several different customers but attach the web folders to a common/central website engine that rewrites requests based on the visiting domain.

When a server gets out of disk space, it is normal to add more disks, arrays or network storage. But Plesk currently supports only single directory for vhosts (web) and/or mailnames (mail). At the moment we are obliged to manually move domain directory to different array and create symlink to it which is not the best practice. Btw cPanel already supports multiple home directories for a long time (/home, /home2, etc). It would be fantastic to have such feature out of the box.