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 48DA27F47 for ; Mon, 23 Feb 2015 10:25:05 -0600 (CST) Received: from cuda.sgi.com (cuda2.sgi.com [192.48.176.25]) by relay3.corp.sgi.com (Postfix) with ESMTP id C97E4AC009 for ; Mon, 23 Feb 2015 08:25:04 -0800 (PST) Received: from mx1.redhat.com (mx1.redhat.com [209.132.183.28]) by cuda.sgi.com with ESMTP id 6ZtZ0AsbN5lAVIi6 (version=TLSv1 cipher=AES256-SHA bits=256 verify=NO) for ; Mon, 23 Feb 2015 08:25:03 -0800 (PST) Message-ID: <54EB5456.5030607@redhat.com> Date: Mon, 23 Feb 2015 10:24:54 -0600 From: Eric Sandeen MIME-Version: 1.0 Subject: Re: Documenting MS_LAZYTIME References: <54E7578E.4090809@redhat.com> <20150221025636.GB7922@thunk.org> <54EB1B19.8050808@gmail.com> In-Reply-To: <54EB1B19.8050808@gmail.com> 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: Austin S Hemmelgarn , Theodore Ts'o Cc: linux-man@vger.kernel.org, Linux API , XFS Developers , Michael Kerrisk , Linux-Fsdevel , Ext4 Developers List , Linux btrfs Developers List On 2/23/15 6:20 AM, Austin S Hemmelgarn wrote: > On 2015-02-20 21:56, Theodore Ts'o wrote: >> On Fri, Feb 20, 2015 at 09:49:34AM -0600, Eric Sandeen wrote: >>> >>>> This mount option significantly reduces writes to the >>>> inode table for workloads that perform frequent random >>>> writes to preallocated files. >>> >>> This seems like an overly specific description of a single workload out >>> of many which may benefit, but what do others think? "inode table" is also >>> fairly extN-specific. >> >> How about somethign like "This mount significantly reduces writes >> needed to update the inode's timestamps, especially mtime and actime. >> Examples of workloads where this could be a large win include frequent >> random writes to preallocated files, as well as cases where the >> MS_STRICTATIME mount option is enabled."? >> >> (The advantage of MS_STRICTATIME | MS_LAZYTIME is that stat system >> calls will return the correctly updated atime, but those atime updates >> won't get flushed to disk unless the inode needs to be updated for >> file system / data consistency reasons, or when the inode is pushed >> out of memory, or when the file system is unmounted.) >> > If you want to list some specific software, it should help with > anything that uses sqlite (which notably includes firefox and > chrome), as well as most RDMS software and systemd-journald. I'm really uneasy with starting to list specific workloads and applications here. It's going to get dated quickly, and will lead to endless cargo-cult tuning. I'd strongly prefer to just describe what it does (reduces the number of certain metadata writes to disk) and leave it at that.... -Eric _______________________________________________ xfs mailing list xfs@oss.sgi.com http://oss.sgi.com/mailman/listinfo/xfs