On Fri, 2003-03-07 at 15:26, Rick Smith wrote:
> A couple questions. Does enabling unwritten extent flagging in XFS
> ultimately reduce filesystem fragmentation? What is the downside of enabling
> unwritten extents other than slower write performance? Thanks.
It should make no difference to physical fragmentation, and in the
normal I/O path unwritten extents should not be used. They only come
into play with space preallocation. In this case they will slow
down I/O somewhat, but provide more security in that you cannot
use unwritten extents to read old data. This is why the prealloc
calls on -d unwritten=0 filesystems are restricted to root.
Steve
--
Steve Lord voice: +1-651-683-3511
Principal Engineer, Filesystem Software email: lord@xxxxxxx
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