Date: Sat, 26 Jan 2002 16:11:12 -0800 From: Terry Lambert <tlambert2@mindspring.com> To: Brad Knowles <brad.knowles@skynet.be> Cc: "Matthew D. Fuller" <fullermd@over-yonder.net>, Mike Meyer <mwm-dated-1012390758.50933b@mired.org>, chip <chip@wiegand.org>, freebsd-chat@freebsd.org Subject: Re: Bad disk partitioning policies (was: "Re: FreeBSD Intaller(was "Re: ... RedHat ...")") Message-ID: <3C5345A0.68D0CE99@mindspring.com> References: <20020123124025.A60889@HAL9000.wox.org> <3C4F5BEE.294FDCF5@mindspring.com> <20020123223104.SM01952@there> <p0510122eb875d9456cf4@[10.0.1.3]> <15440.35155.637495.417404@guru.mired.org> <p0510123fb876493753e0@[10.0.1.3]> <15440.53202.747536.126815@guru.mired.org> <p05101242b876db6cd5d7@[10.0.1.3]> <15441.17382.77737.291074@guru.mired.org> <p05101245b8771d04e19b@[10.0.1.3]> <20020125212742.C75216@over-yonder.net> <p05101203b8788a930767@[10.0.1.14]>
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Brad Knowles wrote: > > Size doesn't matter; percentage does. I've heard somewhere > > (from Terry, I think) that 15% is the 'optimal' setting for this, and > > 10% was a compromise that wasn't too far below optimal, but gave that 5% > > of extra available space. 8% is the current default in newfs(8). > > I disagree. Size does matter. The fragmentation-avoidance > algorithms should still work at the sector/block/cylinder level, but > the total disk space available is now many, many, many, many orders > of magnitude larger than when these algorithms were first created. > > On modern high-capacity disks, 1% should be way more than you > could ever need, in terms of what is required by the > fragmentation-avoidance algorithms. Now, there may be other reasons > why you might want to allocate more than 1% to this reserved disk > space, including the reasons I've previously mentioned. 85% hash fill is 85% hash fill. If you have an arbitrary sized hash table, then why do you somehow think the probability of a hash collision goes down as the size of the hash table goes up, if the relative load on the hash table increases until it is the same percentage of the total hash table size? Please search for "perfect hash" in the NEC "Cite Seer" CS reference database. -- Terry To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-chat" in the body of the message
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