From owner-freebsd-current@FreeBSD.ORG Thu Apr 22 15:31:53 2010 Return-Path: Delivered-To: freebsd-current@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id CA261106566B; Thu, 22 Apr 2010 15:31:53 +0000 (UTC) (envelope-from mavbsd@gmail.com) Received: from mail-wy0-f182.google.com (mail-wy0-f182.google.com [74.125.82.182]) by mx1.freebsd.org (Postfix) with ESMTP id 377F38FC1A; Thu, 22 Apr 2010 15:31:52 +0000 (UTC) Received: by wye20 with SMTP id 20so1899402wye.13 for ; Thu, 22 Apr 2010 08:31:52 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=domainkey-signature:received:received:sender:message-id:date:from :user-agent:mime-version:to:cc:subject:x-enigmail-version :content-type:content-transfer-encoding; bh=4QI4PUfCYDD+MgGyxvK+jjeLEpiBut1qnnidbYQN/JM=; b=x0guPpga4bs57yV7wTa9DYRKGNPFCO6RfdrFGZyLYF1PaRL12y503FLRtemoWicU+F 7dmovUYSXjtLd6J/bD0atSDRD42pbmX3gDT2tKLRJHj8ew/c0qcCtmBcsVaJbyKaRTBA 2wfUgmQoVpgakYHWIv+qh37QpXOC6MVog70y4= DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=sender:message-id:date:from:user-agent:mime-version:to:cc:subject :x-enigmail-version:content-type:content-transfer-encoding; b=RZQfAluTzQUzn9e1EsIj1jgQqPtEArryhO/5wVaZyCTJtJxAlK2/WxaFZX5wxfz/Np U1X+3mzRn3Mux/1ayZtiLlupu3y6PHC1KAqw+w9rjMeEpPjjN3ZIfvvZ1A/fQWTxUdJA n9I/1kkOLWz/CkXffAJ3I98G8SlbDAu9ASDds= Received: by 10.103.84.25 with SMTP id m25mr2348955mul.108.1271950311958; Thu, 22 Apr 2010 08:31:51 -0700 (PDT) Received: from mavbook.mavhome.dp.ua (pc.mavhome.dp.ua [212.86.226.226]) by mx.google.com with ESMTPS id y6sm274676mug.50.2010.04.22.08.31.50 (version=SSLv3 cipher=RC4-MD5); Thu, 22 Apr 2010 08:31:51 -0700 (PDT) Sender: Alexander Motin Message-ID: <4BD06BD9.6030401@FreeBSD.org> Date: Thu, 22 Apr 2010 18:31:37 +0300 From: Alexander Motin User-Agent: Thunderbird 2.0.0.23 (X11/20091212) MIME-Version: 1.0 To: FreeBSD-Current X-Enigmail-Version: 0.96.0 Content-Type: text/plain; charset=KOI8-R Content-Transfer-Encoding: 7bit Cc: freebsd-geom@freebsd.org Subject: Switchover to CAM ATA? X-BeenThere: freebsd-current@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Discussions about the use of FreeBSD-current List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 22 Apr 2010 15:31:53 -0000 Hi. With time passed, CAM-based ATA infrastructure IMHO looks enough mature now to enable it in HEAD. Now we have two new stable drivers ahci(4) and siis(4), covering major part of modern SATA HBAs, `options ATA_CAM` wrapper for ata(4) to supports legacy hardware, and one more improved driver for Marvell HBAs (mvs) is now in development and soon will be present for testing. Together with many other people I have tested above at least on i386, amd64, arm and spart64 architectures. This switchover would give us significant performance improvement on new hardware because of NCQ support in ahci/siis/mvs drivers; improved functionality, including SATA Port Multipliers support, better hot-plug support; and reduced code duplication between ata(4) and cam(4) subsystems and applications. Two issues left at this moment are: 1) POLA breakage due to disk device being renamed from adX to adaY; 2) lack of araraid(4) alternative in new infrastructure. It should be reimplemented in GEOM in some way, but it still wasn't. So what is the public opinion: Is the lack of ataraid(4) fatal or we can live without it? Can we do switchover now, or some more reasons preventing this? If ataraid(4) should be reimplemented in GEOM, then how exactly? One more separate RAID infrastructure in GEOM (third?) looks excessive. Reuse gmirror, gstripe,... code would be nice, but will make them more complicated and could be not easy for RAID0+1 (due to common metadata) and RAID5 (due to lack of module in a base system). -- Alexander Motin