From owner-freebsd-current Wed Oct 21 17:48:56 1998 Return-Path: Received: (from majordom@localhost) by hub.freebsd.org (8.8.8/8.8.8) id RAA05353 for freebsd-current-outgoing; Wed, 21 Oct 1998 17:48:56 -0700 (PDT) (envelope-from owner-freebsd-current@FreeBSD.ORG) Received: from allegro.lemis.com (allegro.lemis.com [192.109.197.134]) by hub.freebsd.org (8.8.8/8.8.8) with ESMTP id RAA05342 for ; Wed, 21 Oct 1998 17:48:52 -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 KAA21393; Thu, 22 Oct 1998 10:18:17 +0930 (CST) Received: (from grog@localhost) by freebie.lemis.com (8.9.1/8.9.0) id KAA01575; Thu, 22 Oct 1998 10:18:15 +0930 (CST) Message-ID: <19981022101814.D1219@freebie.lemis.com> Date: Thu, 22 Oct 1998 10:18:14 +0930 From: Greg Lehey To: "Alok K. Dhir" , current@FreeBSD.ORG Subject: Re: Vinum vs CCD? References: Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii X-Mailer: Mutt 0.91.1i In-Reply-To: ; from Alok K. Dhir on Wed, Oct 21, 1998 at 11:37:13AM -0400 WWW-Home-Page: http://www.lemis.com/~grog 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-current@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG On Wednesday, 21 October 1998 at 11:37:13 -0400, Alok K. Dhir wrote: > > Hi - I recently stumbled accross the existence of vinum in 3.0, and have a > couple of simple questions: > > 1. How does vinum compare to CCD, specifically with regards to > performance and stability? We haven't done much performance testing. My indications, using dd from a raw volume, are that even with the current debug code in Vinum, it will drop performance by about 2% compared to a standard partition. The throughput of both raw partition and raw volume was in the order of 10 MB/s (this is a new IBM IDE drive). I haven't tried it with ccd, but I don't expect much difference. Usingn striping, you can improve overall performance with multiple access only, so it wouldn't show up with a simple dd. When I have time, I'll start doing some serious performance comparisons. > 2. Is anyone using Vinum on an SMP -current box with any horror/success > stories? Yes, with both :-) It seems to work fine with IDE drives, but a couple of people have reported problems in conjunction with CAM and the RAID-5 version. We haven't quite identified the causes, but it seems that under some situations CAM will return an I/O error, and Vinum doesn't always handle it correctly. I'm working on the Vinum side of this problem; the CAM side may be due to incorrect termination which only shows up in typical highly concurrent access patterns which Vinum RAID-5 causes, or in one case it's been suggested that the power supply can't handle the demands of several drives being accessed concurrently. We don't have any specific evidence of a CAM problem. 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-current" in the body of the message