I am using REST api to list directory content. As per rest api documentation each file/dir has an id, which is also the inode number. I want to confirm following things about uniqueness of the id/inode number.

1. Is Inode number unique across all the nodes in cluster.
2. Will Inode number ever be reused for another file(after first file deletion). What will happen in case all inodes in the system are exhausted, will it use some of the deleted files inode numbers?
3. What is the data structure used to store inode number, is it uint64?

I want to enumerate and store the file list across delete/renames and planning to use inode number as unique id, want to make sure no two files will ever share same id for a cluster.