From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from relay.sgi.com (relay3.corp.sgi.com [198.149.34.15]) by oss.sgi.com (Postfix) with ESMTP id D58A97F4E for ; Sun, 26 Oct 2014 12:26:35 -0500 (CDT) Received: from cuda.sgi.com (cuda2.sgi.com [192.48.176.25]) by relay3.corp.sgi.com (Postfix) with ESMTP id 64C9AAC002 for ; Sun, 26 Oct 2014 10:26:32 -0700 (PDT) Received: from greer.hardwarefreak.com (mo-65-41-216-221.sta.embarqhsd.net [65.41.216.221]) by cuda.sgi.com with ESMTP id lGfgdCyGhGM8AIS5 for ; Sun, 26 Oct 2014 10:26:28 -0700 (PDT) Message-ID: <544D2EE1.3080304@hardwarefreak.com> Date: Sun, 26 Oct 2014 12:26:57 -0500 From: Stan Hoeppner MIME-Version: 1.0 Subject: Re: file streams allocator behavior References: <544BF26F.6000708@clear.net.nz> <544C159E.8010408@hardwarefreak.com> <20141026142559.GA61711@bfoster.bfoster> In-Reply-To: <20141026142559.GA61711@bfoster.bfoster> List-Id: XFS Filesystem from SGI List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: xfs-bounces@oss.sgi.com Sender: xfs-bounces@oss.sgi.com To: Brian Foster Cc: Richard Scobie , xfs@oss.sgi.com On 10/26/2014 09:26 AM, Brian Foster wrote: > On Sat, Oct 25, 2014 at 04:26:54PM -0500, Stan Hoeppner wrote: >> On 10/25/2014 01:56 PM, Richard Scobie wrote: >>> Stan Hoeppner said: >>> >>>> How can I disable or change the filestreams behavior so all files go >>>> into the one AG for the single directory test? >>> >>> Hi Stan, >>> >>> Instead of mounting with -o filestreams, would using the chattr flag >>> instead help? >>> >>> See >>> http://xfs.org/docs/xfsdocs-xml-dev/XFS_User_Guide/tmp/en-US/html/ch06s16.html >> >> That won't help. That turns it on (if it's not enabled by default these >> days). I need to turn off the behavior I'm seeing, whether it's due to >> the filestreams allocator or default inode64. Then again it may not be >> possible to turn it off... >> >> Anyone have other ideas on how to accomplish my goal? Parallel writes >> to a single AG on the outer platter edge vs the same to all AGs across >> the entire platter? I'm simply trying to demonstrate the differences in >> aggregate bandwidth due to the extra seek latency of all AGs case. >> > > What about just preallocating the files? Obviously this removes block > allocation contention from your experiment, but it's not clear if that's > relevant to your test. If I create a smaller, but analogous fs to yours, > I seem to get this behavior from just doing an fallocate of each file in > advance. > > E.g., Create directory 0, fallocate 44 files all of which end up in AG > 0. Create directory 1, fallocate 44 files which end up in AG 1, etc. > From there you can do direct I/O overwrites to 44 files across each AG > or 44 files in any single AG. I figured preallocating would get me what I want but I've never used fallocate, nor dd into fallocated files. Is there anything special required here with dd, or can I simply specify the filename to dd, and make sure bs + count doesn't go beyond EOF? Thanks, Stan _______________________________________________ xfs mailing list xfs@oss.sgi.com http://oss.sgi.com/mailman/listinfo/xfs