Suposse I have a doc lib and I want that files in my library could only seen by me.
No access to farm admin
No access by web services
Any ideas?
As was mentioned auditing and notifications of changes in site collection administration can be used to monitor changes in site collection administration access. The farm administrator does not, by default have access to any site collections, but has access to add site collection administrators to the Site Collection from Central Admin. That is where auditing comes in, with a proper audit trail and policy in place you will see (and be notified) of changes in access, but it won’t stop the access.