Chuck Anderson wrote: > On Tue, Jun 10, 2008 at 08:36:31AM -0500, Eric Sandeen wrote: >> journaling filesystem you really shouldn't have any filesystem metadata >> integrity problems on power loss; that is, if you have barriers on >> (which ext3 doesn't by default) and if your storage can pass barriers >> (which lvm doesn't), or if you have drive write cache disabled (which >> hurts performance pretty badly). > > I wasn't aware that LVM destroyed the kind of guarantees about > filesystem metadata being written out to disk that jounaling > filesystems rely on? If so, should we perhaps rethink the decision to > use LVM by default on Fedora installs? I wouldn't say destroys, but at least reduces. See http://lwn.net/Articles/283161/ and associated lkml thread... By default, lvm on fedora is almost always on a single device, and Andi Kleen has sent a patch to allow barriers to pass on that setup: http://lkml.org/lkml/2008/2/15/125 but AFAICT it's not been merged yet. Barriers do have performance impact, which is probably historically why they're off by default on ext3. I'm not totally convinced that it's a good tradeoff. xfs has them on by default; I'm not sure about reiserfs. My patch to enable them by default on ext4 just went upstream. -Eric -- fedora-devel-list mailing list fedora-devel-list@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/fedora-devel-list
