From owner-freebsd-hackers@FreeBSD.ORG Sat Nov 15 22:42:01 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 A3E159CE for ; Sat, 15 Nov 2014 22:42:01 +0000 (UTC) Received: from mail-vc0-x231.google.com (mail-vc0-x231.google.com [IPv6:2607:f8b0:400c:c03::231]) (using TLSv1 with cipher ECDHE-RSA-RC4-SHA (128/128 bits)) (Client CN "smtp.gmail.com", Issuer "Google Internet Authority G2" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id 654A3DF for ; Sat, 15 Nov 2014 22:42:01 +0000 (UTC) Received: by mail-vc0-f177.google.com with SMTP id ij19so4745510vcb.36 for ; Sat, 15 Nov 2014 14:42:00 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=mime-version:date:message-id:subject:from:to:content-type; bh=zmZHK5ibqvhGYTMtroCnR+hgJbAzAFG9k1g48F1m4ws=; b=aTP5L/UG1vVb5IYKyhFeOTNbXfXuT+MPDwpX1078ZR6qQoClqim2bU9ONBAD/5Dkeg Jz5Wk/ZDSDpwKr8QWbL3LqwCA/GdL63AZTXuM8Ej5pRBykxj8GVpe+tUs1VKBSryN4T+ uqFR+Stn/rRDHQKlnrDbbqJtP7ypFzPkghi5ujrMiYuF6e4vS8tD5Ojdjoc9t56U+D6B q3mqsg5kUZfQk+X2+NL99asrknYDEgnKX7umwGLDcMW2/iZzwChtHzM0LkoocWYwkjhA hLK6hFXDfF51oeNmWCVSrK+B3FkGOW86zJQ8ZBbY7AEMLSEQpwA74+K0sy3Zt3MB36PH 3Mug== MIME-Version: 1.0 X-Received: by 10.52.12.198 with SMTP id a6mr12833915vdc.4.1416091320440; Sat, 15 Nov 2014 14:42:00 -0800 (PST) Received: by 10.220.118.19 with HTTP; Sat, 15 Nov 2014 14:42:00 -0800 (PST) Date: Sat, 15 Nov 2014 17:42:00 -0500 Message-ID: Subject: OT-ish SATA port replicators vs. SAS "expanders" From: Zaphod Beeblebrox To: FreeBSD Hackers Content-Type: text/plain; charset=UTF-8 X-Content-Filtered-By: Mailman/MimeDel 2.1.18-1 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: Sat, 15 Nov 2014 22:42:01 -0000 First... seriously... whoever was working on this naming convention thought "expanders" was a good name? Anyways... I don't talk about big piles of disk in any other forum, so I'm asking here. The very first different between SATA port replicators and SAS expanders is that I can find many working examples of the former, while the latter are very scarce. The latter also seem to be expensive, as is anything else labelled with SAS. I have, for some time, been running a ZFS array that makes uses of SATA port replicators. Because I had some CRC errors, someone suggested I look at other SATA ports, and I settled on the Supermicro clone of the LSI 2008. The problem with the LSI 2008 is that it doesn't support SATA port replicators (while it does support SAS expanders). What is the real difference? Is it possible to hack the driver to support (obviously not booting from) SATA port replicators on the LSI?