Date: Wed, 12 Dec 2001 15:37:38 -0800 From: Mike Smith <msmith@freebsd.org> To: Terry Lambert <tlambert2@mindspring.com> Cc: freebsd-arch@FreeBSD.ORG Subject: Re: Real world Root Resizing (was Re: Proposed auto-sizing patch ... Message-ID: <200112122337.fBCNbc103644@mass.dis.org> In-Reply-To: Message from Terry Lambert <tlambert2@mindspring.com> of "Wed, 12 Dec 2001 10:36:19 PST." <3C17A3A3.A439BE21@mindspring.com>
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> Now say you had 99 cylinder groups, and you added one cylinder group. > Your new cylinder group is 0% fiull, and the rest are 90% full. What > is the probability that the new cylinder group will be selected for > new writes? > > The answer is 1%. Ideally, you would want to weight the choice based > on how full each cylinder group was, but that won't happen, since it > defeats the seek optimization if you do that. Actually, this isn't entirely true. The pre-dirpref code would in fact create all new directories in this new cylinder group at least until it was as full (of directories) as the other. And thus new files would also be created there. Dirpref changes this to some degree, and of course it doesn't help for files that already exist. To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-arch" in the body of the message
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