tytso@xxxxxxx wrote: > On Fri, Jan 15, 2010 at 01:52:45PM -0600, Eric Sandeen wrote: >> At least as far as that last bit goes, simply having the extents >> feature is not sufficient; we allow both formats of files to exist >> on a filesystem with the extents feature turned on. > > ... and I guess someone could be appending to a legacy file when the > system crashes. I suppose we can at least exempt extent files from > ordered mode handling. > >> As to the general idea I'll have to give it more thought. :) > > Yeah, and we need to do a lot of performance and functional testing. > Jiaying has done a lot of testing of this in the past couple of > months, but more testing, especially power fail testing, is definitely > a good thing. I also want to do power fail testing for journal > checksums and async commits so we can turn that feature on by default, > since with those features enabled, it almost doubles fs_mark > performance. (Async commit is now badly named, what it does is > reduces the number of write barriers needed from two per commit to > just one. But we do need to test it some more...) At one point google was planning to devise a power-fail test harness. Any news on that? > This was more of a statement of intentions than a "we'll turn this on > by default in 2.3.34". I figure we'll merge first, and then change > the default later, and still later we'll simplify the code paths by > removing the old code path. > > Speaking of which, something more to think about --- does anybody > still care about nobh mode? It was necessary to preserve lowmem for > 32-bit kernels with lots of memory, and it was mainly useful for > database workloads. But with 64-bit kernels, it's not clear the > tradeoffs of not caching the block number are really worth it any > more. What would people think about potentially dropping the nobh > option and write paths from ext4? I have no special love for it personally, and I don't run into fedora users or red hat customers using it, as far as I know. -Eric -- To unsubscribe from this list: send the line "unsubscribe linux-ext4" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
