Physical WiretTiger files per Collection

Hi,

I need to understand the logic mapping between a collection and physical wired tiger (WT) files, have following queries :

  1. Can physical WT files shared across collections, as per my understanding they can’t be.
  2. On what basis physical WT files are created per collection. On what factors does the number of physical WT files created and how the number grows and comes down?
  3. Is there a way to control these physical WT files per collection? What are the implications?

Large number of collections each having large number of WT physical files can create high density of files in the Filesystem which can cause problems. Is this problem seen in real customer scenarios? If yes, how to mitigate?

Also snapshotting the file and transferring to backup media can potentially result in hundred of thousands file per backup which can cause problem to media server. Is this problem seen in real customer scenarios? If yes, how to mitigate?

Thanks.