From owner-freebsd-current Thu Jul 6 8:32:53 2000 Delivered-To: freebsd-current@freebsd.org Received: from khavrinen.lcs.mit.edu (khavrinen.lcs.mit.edu [18.24.4.193]) by hub.freebsd.org (Postfix) with ESMTP id 0B5BD37C61F for ; Thu, 6 Jul 2000 08:32:50 -0700 (PDT) (envelope-from wollman@khavrinen.lcs.mit.edu) Received: (from wollman@localhost) by khavrinen.lcs.mit.edu (8.9.3/8.9.3) id LAA33286; Thu, 6 Jul 2000 11:32:47 -0400 (EDT) (envelope-from wollman) Date: Thu, 6 Jul 2000 11:32:47 -0400 (EDT) From: Garrett Wollman Message-Id: <200007061532.LAA33286@khavrinen.lcs.mit.edu> To: Stijn Hoop Cc: current@FreeBSD.ORG Subject: Large disks (was Re: bin/19635: add -c for grand total to df(1)) In-Reply-To: <20000706131840.B58747@pcwin002.win.tue.nl> References: <16565.962880093@axl.ops.uunet.co.za> <20000706131840.B58747@pcwin002.win.tue.nl> Sender: owner-freebsd-current@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG < said: > Maybe this isn't the right list to ask, but stepping into this: > I bought a 30G drive recently, and I was wondering if the 10% 'rule' > for performance is still really needed. I mean, I lose 3 _gigs_ of > storage space, and otherwise the performance detoriates? That > doesn't make sense to me. Yes. The efficiency of the hashing mechanism used to lay out new blocks on the disk depends only on what fraction of the disk is used, not how much space that represents. (On the other hand, it is unlikely that you are significantly stressing the allocator in any meaningful way.) If you're concerned about wasted disk space, there's a lot to be gained by fiddling with the block sizes, bytes per inode, and other layout parameters. Your 30-GB disk probably has a zillion cylinder groups, which is far too many to actually be helpful in disk layout. When creating a large filesystem, it pays to increase the `-c' parameter as high as newfs will permit. -GAWollman To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-current" in the body of the message