From owner-freebsd-scsi Tue May 18 18:14:59 1999 Delivered-To: freebsd-scsi@freebsd.org Received: from allegro.lemis.com (allegro.lemis.com [192.109.197.134]) by hub.freebsd.org (Postfix) with ESMTP id 30C0514D91 for ; Tue, 18 May 1999 18:14:40 -0700 (PDT) (envelope-from grog@freebie.lemis.com) Received: from freebie.lemis.com (freebie.lemis.com [192.109.197.137]) by allegro.lemis.com (8.9.1/8.9.0) with ESMTP id KAA04466; Wed, 19 May 1999 10:44:25 +0930 (CST) Received: (from grog@localhost) by freebie.lemis.com (8.9.3/8.9.0) id KAA05509; Wed, 19 May 1999 10:44:25 +0930 (CST) Date: Wed, 19 May 1999 10:44:25 +0930 From: Greg Lehey To: Mike Tancsa Cc: freebsd-scsi@FreeBSD.ORG, girgen@partitur.se Subject: Re: Will IDE disks impact SCSI or system performance? Message-ID: <19990519104425.S89091@freebie.lemis.com> References: <37416684.64A54C87@partitur.se> <37420f2c.77551222@mail.sentex.net> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii X-Mailer: Mutt 0.95.4i In-Reply-To: <37420f2c.77551222@mail.sentex.net>; from Mike Tancsa on Wed, May 19, 1999 at 01:11:35AM +0000 WWW-Home-Page: http://www.lemis.com/~grog X-PGP-Fingerprint: 6B 7B C3 8C 61 CD 54 AF 13 24 52 F8 6D A4 95 EF Organization: LEMIS, PO Box 460, Echunga SA 5153, Australia Phone: +61-8-8388-8286 Fax: +61-8-8388-8725 Mobile: +61-41-739-7062 Sender: owner-freebsd-scsi@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.org On Wednesday, 19 May 1999 at 1:11:35 +0000, Mike Tancsa wrote: > On 18 May 1999 19:40:10 -0400, in sentex.lists.freebsd.misc you wrote: That must be me! >> On Tuesday, 18 May 1999 at 15:09:24 +0200, Palle Girgensohn wrote: >>> Hi! >>> >>> Our main internal server, FreeBSD 3.2b with five large SCSI disks, >>> running vinum and softupdates etc... It fast, and we're happy. It runs >>> both filesharing (mainly NFS) and applications. >>> >>> Now some guys here are interested in having a large archive with >>> not-so-important data (read mp3 files...) and suggest a large IDE disk >>> for almost no money at all. >>> >>> My question: will an IDE disk in a now SCSI-only system impact >>> performance for the rest of the system? >> >> Julian sort of answered this, but to be sure: if you run DMA, it >> shouldn't make any difference. If you run it in PIO mode, you can end >> up using up to 90% of the processor in interrupt code, which will make >> it seem like it's grinding to a halt. > > But only when the disk is being accessed no ? Right. Sorry, I suppose I should have mentioned that. > Also, regarding the boot issue someone else mentioned, you should be > able to take the reference to the drive out of the BIOS, and it will > boot from your SCSI device. Yes, somebody (I think it was Julian again) said that. Note that some BIOSes are sneaky and check anyway, and refuse to take "no" for an answer. Greg -- See complete headers for address, home page and phone numbers finger grog@lemis.com for PGP public key To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-scsi" in the body of the message