From owner-freebsd-hackers@FreeBSD.ORG Mon Nov 17 00:49:56 2014 Return-Path: Delivered-To: freebsd-hackers@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by hub.freebsd.org (Postfix) with ESMTPS id 18F0ECC8 for ; Mon, 17 Nov 2014 00:49:56 +0000 (UTC) Received: from smarthost1.sentex.ca (smarthost1.sentex.ca [IPv6:2607:f3e0:0:1::12]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (Client CN "smarthost.sentex.ca", Issuer "smarthost.sentex.ca" (not verified)) by mx1.freebsd.org (Postfix) with ESMTPS id D291A12B for ; Mon, 17 Nov 2014 00:49:55 +0000 (UTC) Received: from [IPv6:2607:f3e0:0:4:f025:8813:7603:7e4a] (saphire3.sentex.ca [IPv6:2607:f3e0:0:4:f025:8813:7603:7e4a]) by smarthost1.sentex.ca (8.14.9/8.14.9) with ESMTP id sAH0ntP7071575 for ; Sun, 16 Nov 2014 19:49:55 -0500 (EST) (envelope-from mike@sentex.net) Message-ID: <54694633.7000906@sentex.net> Date: Sun, 16 Nov 2014 19:49:55 -0500 From: Mike Tancsa Organization: Sentex Communications User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:31.0) Gecko/20100101 Thunderbird/31.2.0 MIME-Version: 1.0 To: FreeBSD Hackers Subject: Re: OT-ish SATA port replicators vs. SAS "expanders" References: <54693866.9040009@sentex.net> In-Reply-To: Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit X-Scanned-By: MIMEDefang 2.75 X-BeenThere: freebsd-hackers@freebsd.org X-Mailman-Version: 2.1.18-1 Precedence: list List-Id: Technical Discussions relating to FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 17 Nov 2014 00:49:56 -0000 On 11/16/2014 7:26 PM, Brandon Vincent wrote: > On Sun, Nov 16, 2014 at 4:51 PM, Mike Tancsa wrote: >> I don think a port multiplier is the same as a SAS expander and a SAS/SATA >> controller does not necessarily support port multipliers. > > You're absolutely correct. The SATA specifications if I recall > correctly, outline that providing support for port multipliers is > optional. Not to mention, the vast majority of chipsets that do have > support for port multipliers only provide the slower command-based > switching method [1], The LSI SAS 2008 chipset is not what you > typically find on the cheap consumer "fake RAID" cards which most > people have [2]. > > Most people who purchase this card are purchasing it for SAS, true > RAID, performance, and reliability. Thus, LSI is only going to provide > support for the far superior SAS expander technology. We also got rid of all those external 4 port PMs and replaced it with one NORCO RPC-4220 The pricing is quite reasonable and less expensive then using PMs and so far MUCH more reliable. ---Mike -- ------------------- Mike Tancsa, tel +1 519 651 3400 Sentex Communications, mike@sentex.net Providing Internet services since 1994 www.sentex.net Cambridge, Ontario Canada http://www.tancsa.com/