1) difference between Authority types, User roles?
Theres a bunch of different authority types. Look at AuthorityType.java for more information.
USER, an authority that identifies a user
ROLE - an authority that identifies a role
GROUP - an authority that identifies a group
OWNER - the special authority that applies to the owner of a node
EVERYONE - the special authority that is interpreted as everyone
GUEST - the special authority that applies to a GUEST (An unknown, unauthenticated user)
2) Max Users in a group restriction – what is the limit, can we increase it. Are there is any Performance issues in case of if more no of users in a group.
I don't know of a limit. You can certainly have a few thousand users in a group without problem.
3) Deleted Items – For how many days the deleted objects are kept/purged in recyle bin? and how can we retrieve it?
Its up to you how you configure it.
4) is there any limit of objects(sub-spaces) inside space?
No
5) what is the File Size limit in a space, can it be configured?
There's a user quota. You can probably put a limit on a space, however I, personally don't know how/
