Date: Tue, 8 May 2007 15:34:41 +0200 (CEST) From: Oliver Fromme <olli@lurza.secnetix.de> To: freebsd-stable@FreeBSD.ORG, marsgmiro@gmail.com Subject: Re: mfs and buildworlds on the SunFire x4600 Message-ID: <200705081334.l48DYf9F085322@lurza.secnetix.de> In-Reply-To: <28edec3c0705072045s18a2cb53ia4f66030e4e3fb22@mail.gmail.com>
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Mars G. Miro wrote: > Oliver Fromme wrote: > > Mars G. Miro wrote: > > > there's been a lot of threads in teh past that a buildworld on mfs > > > increases speed --- tho it might not be the appropriate test for > > > high-end machines (speaking of w/c I just gots a T2000). > > > > It depends on what exactly you want to test, and for > > what reason. You probably have already wasted much > > more time with your experiments and testing than you > > can ever save by using mfs for buildworld. > > wasted my time? dont think so. > > now we know buildworld on mfs dont really matter on high-end machines, No, we knew that before. I could have told you. :-) That was the first thing I tested when I first had access to a machine with sufficient RAM, about 10 years ago. I put /usr/src on an MFS disk, ran buildworld, and was disappointed. > so teh conclusion would be, buildworld isnt teh appropriate test if > mfs does really speed things up, other apps/tools may be much more > appropriate --- that or, does mfs speeding things up really work? > remains to be seen ... The only case for which a memory file system is really faster is when you're handling a huge number of inodes, for example the ports collection. And even then a real disk isn't much slower as soon as the whole bunch is in the cache. > > > there's prolly other appropriate apps/tools for mfs-testing ... > > > > I don't think it makes much sense to benchmark mfs. > > It is a known fact that a real tmpfs (like Solaris and > > Linux have) would be better. I think it's even listed > > on the FreeBSD ideas web page, but nobody is actively > > working on it, AFAIK. On the other hand, I'm not 100% > > convinced that it would be worth the effort either. > > > > it does to me, however, and perhaps other people too ;-) Why? I wonder why you are so eager to test MFS? > > It would be interesting to see how ZFS on a swap-backed > > vnode device would perform on FreeBSD 7-current (with > > and without compression). You didn't comment on that one. Aren't you interested in how a ZFS-based memory disk would perform, as opposed to a UFS-based one (a.k.a. "MFS")? (Of course, performance isn't everything. ZFS has other features such as compression, checksums and dynamic growth that might be very useful for a memory disk.) Best regards Oliver -- Oliver Fromme, secnetix GmbH & Co. KG, Marktplatz 29, 85567 Grafing b. M. Handelsregister: Registergericht Muenchen, HRA 74606, Geschäftsfuehrung: secnetix Verwaltungsgesellsch. mbH, Handelsregister: Registergericht Mün- chen, HRB 125758, Geschäftsführer: Maik Bachmann, Olaf Erb, Ralf Gebhart FreeBSD-Dienstleistungen, -Produkte und mehr: http://www.secnetix.de/bsd "To this day, many C programmers believe that 'strong typing' just means pounding extra hard on the keyboard." -- Peter van der Linden
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