From owner-freebsd-hackers Sat Jan 23 23:45:34 1999 Return-Path: Received: (from majordom@localhost) by hub.freebsd.org (8.8.8/8.8.8) id XAA26345 for freebsd-hackers-outgoing; Sat, 23 Jan 1999 23:45:34 -0800 (PST) (envelope-from owner-freebsd-hackers@FreeBSD.ORG) Received: from panzer.plutotech.com (panzer.plutotech.com [206.168.67.125]) by hub.freebsd.org (8.8.8/8.8.8) with ESMTP id XAA26336 for ; Sat, 23 Jan 1999 23:45:22 -0800 (PST) (envelope-from ken@panzer.plutotech.com) Received: (from ken@localhost) by panzer.plutotech.com (8.9.2/8.8.5) id AAA07177; Sun, 24 Jan 1999 00:44:52 -0700 (MST) From: "Kenneth D. Merry" Message-Id: <199901240744.AAA07177@panzer.plutotech.com> Subject: Re: SCSI question... and some enum idea In-Reply-To: <19990123041739.G4581@nacamar.net> from "Karsten W. Rohrbach" at "Jan 23, 99 04:17:39 am" To: rohrbach@nacamar.net Date: Sun, 24 Jan 1999 00:44:52 -0700 (MST) Cc: freebsd-hackers@FreeBSD.ORG X-Mailer: ELM [version 2.4ME+ PL28s (25)] MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: owner-freebsd-hackers@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG Karsten W. Rohrbach wrote... > i got a box with 2940u2w(aic789x) and raid array on an infortrend ift3102 > running here. the ift does create multiple luns for the different logical > disks - and it works excellent for me. > > btw, what came to my mind in this context was the enumeration of disk > devices (da?)... on some $$$ un*x boxes you got a scheme where the device > inode enumeration is fixed to the bus, scsi id and lun of the device > (pretty good idea that) so that if you sometimes add or remove your second > disk the third doesnt get the second and gets a mount error with wrong > filesystem type... so you would use /dev/disk/bus0id0lun0a or something as > root device... is this a good idea or is it rather nasty? i am often > swapping in/out our cd toaster of my department which is jumpered to id4 > and i'm a lazy bastard, so my drive on id5 and the cdrom on id6 change > device numbers sometimes... You can hardwire devices in your kernel config file to achieve the same effect, with more flexibility. You can do things like: controller ahc0 controller scbus0 at ahc0 device da0 at scbus0 target 0 unit 0 device cd0 at scbus0 target 5 unit 0 device cd1 at scbus0 target 6 unit 0 device cd2 at scbus0 target 4 unit 0 See LINT, or cam(4) for more details. [ which reminds me of a PR I need to fix and close ] Ken -- Kenneth Merry ken@plutotech.com To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message