regarding journaling, there is the counter argument that you do not need to do the same job twice,
in the sense that we already spend a considerable amount of time retaining the WAL in postgresql,
no need to redo the same on FS level.
There's a difference in the file system integrity and the DB integrity. PG will keep the DB integrity just fine without the file system journaling. The journaling just makes recovery from crash that much faster. ie, running fsck on 6TB of disk storage takes a LONG time, sometimes hours, but with the journal enabled, it takes a few seconds.