I just tried several times to make sure I didn't do anything wrong.
I use
pg_dump -U postgres -E UTF8 -F c -b -v -a dbcontent -f data.backup
then
pg_restore -a -d dbcontent data.backup
to restore a db, and the data dir's size on the source machine is
56GB, after I restored data on the target machine, it 130GB, I did
vacuum full but nothing changed.
is there anything wrong with the db?