From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from relay.sgi.com (relay2.corp.sgi.com [137.38.102.29]) by oss.sgi.com (Postfix) with ESMTP id CA58C7F47 for ; Tue, 25 Aug 2015 16:44:53 -0500 (CDT) Received: from cuda.sgi.com (cuda1.sgi.com [192.48.157.11]) by relay2.corp.sgi.com (Postfix) with ESMTP id AA5A830404E for ; Tue, 25 Aug 2015 14:44:50 -0700 (PDT) Received: from sandeen.net (sandeen.net [63.231.237.45]) by cuda.sgi.com with ESMTP id xsgCWpwKxW21fkfP for ; Tue, 25 Aug 2015 14:44:48 -0700 (PDT) Message-ID: <55DCE1CF.5030708@sandeen.net> Date: Tue, 25 Aug 2015 16:44:47 -0500 From: Eric Sandeen MIME-Version: 1.0 Subject: Re: Performance impact of mkfs.xfs vs mkfs.xfs -f References: In-Reply-To: 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: Shrinand Javadekar , xfs@oss.sgi.com On 8/25/15 3:32 PM, Shrinand Javadekar wrote: > Hi, > > I have 23 disks formatted with XFS on a single server. The workload is > Openstack Swift. See this email from a few months ago about the > details: > > http://oss.sgi.com/archives/xfs/2015-06/msg00108.html > > I am observing some strange behavior and would like to get some > feedback about why this is happening. > > I formatted the disks with xfs (mkfs.xfs) and deployed Openstack Swift > on it. Writing 100GB of data into Swift in batches of 20GB each gave > us the following throughput: > > 20 GB: 93MB/s > 40 GB: 65MB/s > 60 GB: 52MB/s > 80 GB: 50MB/s > 100 GB: 48MB/s > > I then re-formatted the disks with mkfs.xfs -f and ran the experiment > again. This time I got the following throughput: > > 20 GB: 118MB/s > 40 GB: 95MB/s > 60 GB: 74MB/s > 80 GB: 68MB/s > 100 GB: 63MB/s > > I've seen similar results twice. How did you do the above twice, out of curiosity? If it's the same set of disks, the 3rd mkfs would require "-f" to overwrite the old format. > Any ideas why this might be happening? With the paucity of information you've provided, nope! What version of xfsprogs are you using? What was the output of mkfs.xfs each time; did the geometry differ? -f sets force_overwrite, which only does 3 things: 1) overwrite existing filesystem signatures 3) zeros out old xfs structures on disk 2) allow mkfs to proceed on a misaligned device I don't see why any of those behaviors would change runtime behavior. Maybe you have other variables in your performance testing, and two tests isn't enough to sort out noise? -Eric > Thanks in advance. > -Shri > > _______________________________________________ > xfs mailing list > xfs@oss.sgi.com > http://oss.sgi.com/mailman/listinfo/xfs > _______________________________________________ xfs mailing list xfs@oss.sgi.com http://oss.sgi.com/mailman/listinfo/xfs