I'm using a NFS system. I noticed that once I set setGID to a file, e.g.
chmod g+s myfile
The file become un-readable (even root user is not able to access it). if I try to read, i got:
tail myfile
cannot open `myfile' for reading: Permission denied
What could be problem? using ls -l or getfacl, I can see owner,group, other all have read permission though:
ls -l
-rw-r-Sr--+ 1 oracle dba 5 Sep 19 07:51 myfile
getfacl myfile
# file: myfile
# owner: oracle
# group: dba
user::rw-
group::r--
mask::rwx
other::r--