Klever

At the moment all Klever data is stored on an instance disk that is fast, but not reliable. It has sense to store a database and directory media to a separate, slow but reliable volume. I suggest to create and to attach volumes of 200 GB by default, but, perhaps, there may be an option to adjust the volume size.

It is important to check whether volumes will operate well after various operations with instances, especially, after resizing (#10767).

A very advanced feature that may be rather useful nevertheless is an ability to attach an existing volume to a new instance. This may be helpful, e.g. when an instance fails but the user would like to use its volume further. I am not sure that this will happen often, so, maybe it will be better to do this manually, though, this is not trivial.