Had not seen it from the FAQ. Thanks for the link.
Le Sunday 06 February 2011 00:04:55, Richard Toohey a icrit : > On 6/02/2011, at 9:31 AM, Jean-Francois wrote: > > Hi, > > > > Right. Could you please describe in few words whet softdeps is ? > > http://www.openbsd.org/faq/faq14.html#SoftUpdates > > Wouldn't you rather let Nick & the other OpenBSD developers *WORK* on > OpenBSD? I would. > > Rather than answering questions that are in the docs? Or can be found in > Google? > > Or the code? Or from your own experiments? > > Thanks. > > > Thanks. > > J-F > > > > Le Saturday 05 February 2011 20:11:17, Nick Holland a icrit : > >> On 02/05/11 09:32, Jean-Francois wrote: > >>> Hello, > >>> > >>> I just read some extracts of a paper, study from Margo Seltzer & Keith > >>> A. Smith from Harvard university, a comparison of LFS & FFS. > >> > >> the paper from 1995?? > >> > >> Dude. That's a LONG time ago in the computer world. It is also a very > >> non-specific "Log-structured file system", which may or may not have any > >> real-world counterpart here 16 years later (yes, some modern file > >> systems are "logging" FSs, but...are they descendants of this 1995 LFS? > >> Or was this LFS a dead-end for real-world reasons that never show up in > >> academic papers? (I'm sure I could do some more research on this, but > >> it's your question, not mine :) > >> > >>> Basic questions from my side, is FFS-2 better than FFS in the sense of > >>> dealing with creation of many small files, and is fragmentation less > >>> than with FFS ? > >> > >> Please describe the fragmentation problem you have /observed/... I do a > >> lot to torment file systems, and never seen anything that looked like a > >> PROBLEM caused by fragmentation on OpenBSD. If you aren't seeing a real > >> problem, how can you benefit from optimizing? > >> > >>> Are other file systems with some improvement of performance compared to > >>> FFS available for OpenBSD ? > >> > >> Short answer: there are two file systems provided for day-to-day use on > >> OpenBSD: FFS and FFS2. FFS is the general purpose OS, FFS2 is for very > >> large file systems which can't be handled by FFS. Nice and simple. > >> > >> Other file systems that OpenBSD supports are for cross-system > >> compatibility, not for "better" anything on OpenBSD, at least at this > >> time (wouldn't mind seeing a working HAMMER port, of course). > >> > >> And...as FFS2 is used for larger file systems, I think it is safe to say > >> that putting lots of small files on huge file systems is much worse than > >> putting lots of small files on a few (or a lot) of small file systems. > >> > >> However, if you are looking at writing lots of small files, make sure > >> you you are using softdeps, you will get a very large performance gain > >> (I'm not talking 10% -- more like 10x!). You may find you get much > >> better real performance than many logging systems give. > >> > >> Nick.
