From owner-freebsd-questions@FreeBSD.ORG Mon Jun 19 02:44:39 2006 Return-Path: X-Original-To: freebsd-questions@freebsd.org Delivered-To: freebsd-questions@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 48A3116A479; Mon, 19 Jun 2006 02:44:39 +0000 (UTC) (envelope-from user@dhp.com) Received: from shell.dhp.com (shell.dhp.com [199.245.105.1]) by mx1.FreeBSD.org (Postfix) with ESMTP id 2C1D443D6A; Mon, 19 Jun 2006 02:44:38 +0000 (GMT) (envelope-from user@dhp.com) Received: by shell.dhp.com (Postfix, from userid 896) id 148C831323; Sun, 18 Jun 2006 22:44:37 -0400 (EDT) Date: Sun, 18 Jun 2006 22:44:36 -0400 (EDT) From: Ensel Sharon To: Eric Anderson In-Reply-To: <449606B8.5080106@centtech.com> Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Cc: freebsd-fs@freebsd.org, freebsd-questions@freebsd.org Subject: Re: Please help - adaptec 2820sa not ... RESOLVED X-BeenThere: freebsd-questions@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: User questions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 19 Jun 2006 02:44:39 -0000 On Sun, 18 Jun 2006, Eric Anderson wrote: > > 6.1 sysinstall does in fact see both 2820sa controllers, and when I put in > > a single 160GB sata drive, it does see that single drive and I can install > > onto it, etc. > > > > Sysinstall does _not_ see my 2.7TB raid6 array. I suspect that if it were > > smaller than 2TB, it would see it correctly. > > > > I have a number of options with which to deal with this, all of which > > involve either wasting money or wasting disk space. Fantastic. > > Right - FreeBSD doesn't recognize >2TB LUNs. You should make two LUNs, > and concat them or stripe them with GEOM. Don't use the large partition > for the OS either. > > You shouldn't waste either disk space or money. Let's say I have 8 disks. Let's say I require raid6. If I make one array, I lose 25% to raid overhead. If I make two arrays, I lose 50% to raid overhead. So it would seem that my inability to use a >2TB LUN does indeed lose me both space and waste money. My solution is to use two disks as a mirror, and use the other six for a raid6 array, thus losing 3/8 to raid overhead instead of 4/8, but it's still worse than 2/8 which is what I wanted to do ... Perhaps I misunderstand you ?