On Tue, November 3, 2009 16:36, Nils Goroll wrote: > > No point in trying to preserve a naive mental model that >> simply can't stand up to reality. > > I kind of dislike the idea to talk about naiveness here.
Maybe it was a poor choice of words; I mean something more along the lines of "simplistic". The point is, "space" is no longer as simple a concept as it was 40 years ago. Even without deduplication, there is the possibility of clones and compression causing things not to behave the same way a simple filesystem on a hard drive did long ago. > Being able to give guarantees (in this case: reserve space) can be vital > for > running critical business applications. Think about the analogy in memory > management (proper swap space reservation vs. the oom-killer). In my experience, systems that run on the edge of their resources and depend on guarantees to make them work have endless problems, whereas if they are not running on the edge of their resources, they work fine regardless of guarantees. For a very few kinds of embedded systems I can see the need to work to the edges (aircraft flight systems, for example), but that's not something you do in a general-purpose computer with a general-purpose OS. > But I realize that talking about an "implicit expectation" to give some > motivation for reservations probably lead to some misunderstanding. > > Sorry, Nils There's plenty of real stuff worth discussing around this issue, and I apologize for choosing a belittling term to express disagreement. I hope it doesn't derail the discussion. -- David Dyer-Bennet, d...@dd-b.net; http://dd-b.net/ Snapshots: http://dd-b.net/dd-b/SnapshotAlbum/data/ Photos: http://dd-b.net/photography/gallery/ Dragaera: http://dragaera.info _______________________________________________ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
