why does we take so many attention to fsync issue?
but there are also table spaces in tmpfs, wal in tmpfs, disks with cache without bbu, writeback writes and fs without ordering and journal, any CLOUDS, etc etc... in our real world installations.
more over not all of these issues are usually in dba's medium, and what dba really have to do -- is to accept ugly bottom storage properties and DO properly PITR/standby.
and if we have PITR then "fsync or not fsync" in master host doesn't matter so much. and could matter providing fsync in archive host. but doing fsync in archive -- it is workaround for archive_command realization.
in conclusion -- imho, full-page writes is more sensual than fsync when we guarantee PITR.
-- misha