more than 6000 subfolders in the same level

[Chris]

Dear All,

I'm going to use a public namespace with more than 6000 folders and
subfolders.

On the local ext4-filesystem the nested IMAP subfolders will all be in the
same directory:

/var/vmail/public/folder1
/var/vmail/public/folder1.subfolder1a
/var/vmail/public/folder1.subfolder1b
...

Is this possible without any performance issues? Would it be better to use
"real" subfolders with / as separator? Is / separator for public namespace
and . for private namespace possible?

- Chris