On Tue, Jul 08, 2014 at 03:22:31PM +0200, Jean-Pierre André wrote: > Richard W.M. Jones wrote: > >Now copy data to the filesystem and issue an fstrim command, and the > >underlying loop file should become sparse: > > ... if the underlying fs supports a BLKDISCARD ioctl requests, > which is not the case for NTFS...
Right, although that would be a little bit strange & rare! More commonly you'll be using ntfs-3g backed by a block device (I just used a loopback because it's very convenient for testing). If you look at: /sys/block/<device_name>/queue/discard* you can see if discard is supported by your block device. IIRC discard_max_bytes must be > 0 for TRIM to be supported at all by the block device. Thanks for the review, I'll see what I can do in a few days. Rich. -- Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones Read my programming and virtualization blog: http://rwmj.wordpress.com virt-df lists disk usage of guests without needing to install any software inside the virtual machine. Supports Linux and Windows. http://people.redhat.com/~rjones/virt-df/ ------------------------------------------------------------------------------ Open source business process management suite built on Java and Eclipse Turn processes into business applications with Bonita BPM Community Edition Quickly connect people, data, and systems into organized workflows Winner of BOSSIE, CODIE, OW2 and Gartner awards http://p.sf.net/sfu/Bonitasoft _______________________________________________ ntfs-3g-devel mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/ntfs-3g-devel
