Slower performance with ext4

[Rashkae]

> 
> Journaling only for metadata is not 'as much journaling as any other 
> canditates.' You cannot say metadata journaling only as equivalent to 
> the data and metadata journaling that is possible with ext3. XFS's 
> journaling only provides filesystem metadata consistency which is why 
> you get files full of NULLs after a crash/power out. MTAs rely on fsync 
> calls and how a filesystem behaves in regards to fsync requests is the 
> real determiner of whether there is a data guarantee or not. XFS does 
> not provide data guarantee. I


This is completely false,, XFS gives as much data guarantee as the other
filesystems in respects to an fsync.  The reason files can have Null
bytes appended to them in XFS is because XFS, unlike ext3, will commit
meta data changes out of order from the data actually being written to
disk, but this has nothing to do with fsync, which works as intended.