From owner-freebsd-scsi Mon Aug 17 15:30:37 1998 Return-Path: Received: (from majordom@localhost) by hub.freebsd.org (8.8.8/8.8.8) id PAA08203 for freebsd-scsi-outgoing; Mon, 17 Aug 1998 15:30:37 -0700 (PDT) (envelope-from owner-freebsd-scsi@FreeBSD.ORG) Received: from uni4nn.gn.iaf.nl (osmium.gn.iaf.nl [193.67.144.12]) by hub.freebsd.org (8.8.8/8.8.8) with SMTP id PAA08191 for ; Mon, 17 Aug 1998 15:30:32 -0700 (PDT) (envelope-from wilko@yedi.iaf.nl) Received: by uni4nn.gn.iaf.nl with UUCP id AA07591 (5.67b/IDA-1.5); Tue, 18 Aug 1998 00:01:21 +0200 Received: (from wilko@localhost) by yedi.iaf.nl (8.8.8/8.6.12) id XAA14036; Mon, 17 Aug 1998 23:17:28 +0200 (CEST) From: Wilko Bulte Message-Id: <199808172117.XAA14036@yedi.iaf.nl> Subject: Re: Multiple hosts sharing drive(s) on a shared SCSI bus In-Reply-To: <35D869FF.31064557@Boolean.Net> from "Kurt D. Zeilenga" at "Aug 17, 98 10:35:59 am" To: Kurt@boolean.net (Kurt D. Zeilenga) Date: Mon, 17 Aug 1998 23:17:28 +0200 (CEST) Cc: scsi@FreeBSD.ORG X-Organisation: Private FreeBSD site - Arnhem, The Netherlands X-Pgp-Info: PGP public key at 'finger wilko@freefall.freebsd.org' X-Mailer: ELM [version 2.4ME+ PL38 (25)] Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: owner-freebsd-scsi@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.org As Kurt D. Zeilenga wrote... > I have three systems with dual channel UW SCSI (7895) running > -current w/ CAM (latest snapshot). Currently, the second > channel is unused on all three system. I'd like to use > these channels to provided shared (but not concurrent) access > to a tape drive and, possibly a disk drive, on a shared bus. > > Will this work? SCSI supports this concept, it's called multiple initiator. Obviously you'll have to set each hosts for it's own unique scsi id. Keep in mind that if the bus runs at Ultra speeds you have a severely limited cable length. (1.5 meters, maybe you'll be able to get it to work with something a bit longer). For professional use we exclusively use differential scsi (we == Digital ^H^H^H^H^ Compaq). This kind of stuff is done in VMS and Digital Unix clusters. And please note that if some host does a scsi bus reset your tape will loose it's position. Some (all?) rewind etc. Not nice if you're doing (incremental) dumps on the nrst device obviously. Wilko _ ______________________________________________________________________ | / o / / _ Bulte email: wilko @ yedi.iaf.nl |/|/ / / /( (_) Arnhem, The Netherlands WWW: http://www.tcja.nl ______________________________________________ Powered by FreeBSD __________ To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-scsi" in the body of the message