Date: Wed, 03 Apr 1996 19:30:39 -0800 From: David Greenman <davidg@Root.COM> To: HMG coA reductase <s_koyin@eduserv.its.unimelb.EDU.AU> Cc: freebsd-questions@freebsd.org Subject: Re: sysinstall's newfs Message-ID: <199604040330.TAA18085@Root.COM> In-Reply-To: Your message of "Thu, 04 Apr 1996 13:05:04 %2B1000." <199604040305.NAA10219@eduserv.its.unimelb.EDU.AU>
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>G'day all. I have some observations regarding the state of the filesystem >after installing a new copy of FreeBSD. Apparently the sysinstall defaults >for newfs are grossly inappropriate and lead to a badly optimised file- >system. "Apparantly", but nonetheless are correct and intentional. >Some note worthy points are: >1. Absence of rotational position table The rotational position table is only useful if you wish to interleave the block allocations. On any modern drive, this would be a big lose. The rotational position table is a no-op when 'rotdelay' is 0 (which, again, for modern drives is the best value). >2. ntrak value of 1, which should be equal to the no. of heads, or > tracks per cylinder. >3. nsect == npsect == spc which does not tally with the disklabel values. This is a matter of modern drives having a variable number of sectors per track - making any "real" choice impossible. The values that sysinstall has chosen are used because they escentially disable most of the special allocation strategy that ancient drives use to need. Further, the specific values were chosen to optimize the cylinder group allocation. -DG David Greenman Core-team/Principal Architect, The FreeBSD Project
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