Creating sparse file on XFS and EXT3 has different results

Greg Freemyer greg.freemyer at gmail.com
Fri Aug 5 08:11:07 EDT 2011


There are no "specs" as to how a sparse file is handled in response to
writes.

Sparse is mostly beneficial when the holes are very large.

If an app really wants to have minimal on disk space, you should
pre-allocate space with fallocate.

You may even need to hole punch after the writes.  Both xfs and ext4 support
both fallocate and hole punching. (I don't know the userspace call to hole
punch.  I think its a relatively new feature for ext4.)

Greg
On Aug 4, 2011 10:16 PM, "Ashish Sangwan" <ashishsangwan2 at gmail.com> wrote:
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