From owner-freebsd-arch Fri Dec 7 14:57:47 2001 Delivered-To: freebsd-arch@freebsd.org Received: from apollo.backplane.com (apollo.backplane.com [216.240.41.2]) by hub.freebsd.org (Postfix) with ESMTP id E45B937B416 for ; Fri, 7 Dec 2001 14:57:45 -0800 (PST) Received: (from dillon@localhost) by apollo.backplane.com (8.11.6/8.9.1) id fB7MvjE95211; Fri, 7 Dec 2001 14:57:45 -0800 (PST) (envelope-from dillon) Date: Fri, 7 Dec 2001 14:57:45 -0800 (PST) From: Matthew Dillon Message-Id: <200112072257.fB7MvjE95211@apollo.backplane.com> To: Sheldon Hearn Cc: Kirk McKusick , freebsd-arch@FreeBSD.ORG Subject: Re: Using a larger block size on large filesystems References: <31807.1007732134@axl.seasidesoftware.co.za> Sender: owner-freebsd-arch@FreeBSD.ORG Precedence: bulk List-ID: List-Archive: (Web Archive) List-Help: (List Instructions) List-Subscribe: List-Unsubscribe: X-Loop: FreeBSD.ORG :Hi Matt, : :I already have patches for newfs, sysinstall and the tuning(7) manual :page which simply make 16384/2048 the default. : :However, I remember people expressing concerns with using these parameters :for very small filesystems. : :I can't find any negative performance impact for very small filesystems. : :The only other thing I can think of is what obrien suggested. He told :me that it might be that people are wary of a filesystem that contains :only a single cylinder group, as this means you only have one :superblock. : :Is this really something to worry about? Is there some other reason why :we shouldn't just make 16384/2048 the blanket default? : :Ciao, :Sheldon. I think you've hit the nail on the head. I think we do want at least two cylinder groups, but beyond that I think even the smallest hard drive will do just fine with 16K/2K. Floppies and other types of media are already hardwired in /etc/disktab so we shouldn't have to worry about them. In considering Kirk's posting in regards to the 512/4K -> 1K/8K debate, I think we are in exactly the same situation here and should just maintain a stiff upper lip and change the default to 2K/16K. People with 'special' requirements are smart enough to manage the parameters themselves. 2K/16K is a good default for more of our users then 1K/8K was. -Matt To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-arch" in the body of the message