From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: with ECARTIS (v1.0.0; list xfs); Fri, 28 Jul 2006 13:55:51 -0700 (PDT) Received: from talk.nabble.com (www.nabble.com [72.21.53.35]) by oss.sgi.com (8.12.10/8.12.10/SuSE Linux 0.7) with ESMTP id k6SKtZDW021555 for ; Fri, 28 Jul 2006 13:55:35 -0700 Received: from [72.21.53.38] (helo=jubjub.nabble.com) by talk.nabble.com with esmtp (Exim 4.50) id 1G6YGg-0000xD-1I for xfs@oss.sgi.com; Fri, 28 Jul 2006 12:45:06 -0700 Message-ID: <5545990.post@talk.nabble.com> Date: Fri, 28 Jul 2006 12:45:06 -0700 (PDT) From: calembour Subject: write back cache and barriers MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Sender: xfs-bounce@oss.sgi.com Errors-To: xfs-bounce@oss.sgi.com List-Id: xfs To: xfs@oss.sgi.com Hi, I don't have a deep knowledge about filesystems and I've few experiences with raid configuration, so I need someone who can answer some questions about write back cache and barriers. I have two sata hd (sda, sdb) configured in bios-raid 0 and relative device created by dmraid on boot (nvidia_ihfaaicb). (1) what should I do to know if the write back cache is enabled or not ? (2) if the write cache is enabled on both sda and sdb this mean that is enabled also on the raid device (/dev/mapper/nvidia_ihfaaicb) ? (3) how should I do to enable/disable the write cache on the raid device ? If I try mounting a xfs filesystem I get a message like "barriers are not supported by this device" but if I mount a ext3 or a reiserfs filesystem respectively with options barrier=1 and barrier=flush they don't complain. If I mount the reiserfs I explicity get a message like "using barriers". So who tells the truth ?? (4) is there a way to know if the raid device supports barrier or not ? (5) is there a (not dangerous) test I can do to figure out if barriers are really enabled and used with ext3 and reiserfs filesystems ? Thanks for reading the message Marco -- View this message in context: http://www.nabble.com/write-back-cache-and-barriers-tf2017234.html#a5545990 Sent from the Xfs - General forum at Nabble.com.