From owner-freebsd-scsi@FreeBSD.ORG Wed May 14 15:44:42 2003 Return-Path: Delivered-To: freebsd-scsi@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 7A65837B401 for ; Wed, 14 May 2003 15:44:42 -0700 (PDT) Received: from rootlabs.com (root.org [67.118.192.226]) by mx1.FreeBSD.org (Postfix) with SMTP id EBB0543F3F for ; Wed, 14 May 2003 15:44:39 -0700 (PDT) (envelope-from nate@rootlabs.com) Received: (qmail 79389 invoked by uid 1000); 14 May 2003 22:44:41 -0000 Date: Wed, 14 May 2003 15:44:41 -0700 (PDT) From: Nate Lawson To: scsi@freebsd.org Message-ID: <20030514151752.B79363@root.org> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Subject: SCSI geometry calculation? X-BeenThere: freebsd-scsi@freebsd.org X-Mailman-Version: 2.1.1 Precedence: list List-Id: SCSI subsystem List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 14 May 2003 22:44:42 -0000 I am reviewing our current geometry calculation and have a few questions. Here is what I found in my review. Most drivers use >1G: 255/63, else 64/32. Exceptions are: * aac - >=2G: 255/63, >=1G 128/32, else 64/32 * aha - same * amr - >2G: 255/63, else 64/32 * asr - >4G: 255/63, >2G: 128/63, >1G: 65/63, else 64/32 * ata-raid - always 255/63 * bt - same as aha * ciss - 255/32 if fault_tolerance is invalid else what the logical drive reports. * mlx - if MLX_GEOM_256_63 set: 255/63, else 128/32. Since nothing seems to set mlx_geom, 128/32 is probably always used. * mly - same * pst - always 255/63 * twe - >2G: 255/63, else 64/32 Some of these seem to be bugs, especially for volumes exactly on a boundary (2G). Since many of the stranger ones are RAID controllers, they won't have to support drive portability to other controllers. What should actually be done in CALC_GEOMETRY? -Nate