From owner-freebsd-current@FreeBSD.ORG Mon Mar 31 17:37:03 2008 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 113BA106566C for ; Mon, 31 Mar 2008 17:37:03 +0000 (UTC) (envelope-from freebsd-current@m.gmane.org) Received: from ciao.gmane.org (main.gmane.org [80.91.229.2]) by mx1.freebsd.org (Postfix) with ESMTP id C3DF48FC24 for ; Mon, 31 Mar 2008 17:37:02 +0000 (UTC) (envelope-from freebsd-current@m.gmane.org) Received: from list by ciao.gmane.org with local (Exim 4.43) id 1JgNwF-0005b5-Ut for freebsd-current@freebsd.org; Mon, 31 Mar 2008 17:36:56 +0000 Received: from 213.202.123.81 ([213.202.123.81]) by main.gmane.org with esmtp (Gmexim 0.1 (Debian)) id 1AlnuQ-0007hv-00 for ; Mon, 31 Mar 2008 17:36:55 +0000 Received: from ivoras by 213.202.123.81 with local (Gmexim 0.1 (Debian)) id 1AlnuQ-0007hv-00 for ; Mon, 31 Mar 2008 17:36:55 +0000 X-Injected-Via-Gmane: http://gmane.org/ To: freebsd-current@freebsd.org From: Ivan Voras Date: Mon, 31 Mar 2008 19:36:56 +0200 Lines: 7 Message-ID: Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-Complaints-To: usenet@ger.gmane.org X-Gmane-NNTP-Posting-Host: 213.202.123.81 User-Agent: Thunderbird 1.5.0.14 (Windows/20071210) X-Enigmail-Version: 0.94.1.0 Sender: news Subject: Are large RAID stripe sizes useful with FreeBSD? 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: Mon, 31 Mar 2008 17:37:03 -0000 Most of new hardware RAID controllers offer stripe sizes of 128K, 256K and some also have 512K and 1M stripes. In the simplest case of RAID0 of two drives, knowing that the data is striped across the drives and that FreeBSD issues IO request of at most 64K, is it useful to set stripe sizes to anything larger than 32K? I suppose something like TCQ would help the situation but does anyone know how is this situation usually handled on the RAID controllers?