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.
