From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pb0-f46.google.com ([209.85.160.46]:61169 "EHLO mail-pb0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754262Ab2ISL2e (ORCPT ); Wed, 19 Sep 2012 07:28:34 -0400 Received: by pbbrr13 with SMTP id rr13so2245901pbb.19 for ; Wed, 19 Sep 2012 04:28:33 -0700 (PDT) Message-ID: <5059AC5E.1030003@gmail.com> Date: Wed, 19 Sep 2012 19:28:30 +0800 From: ching MIME-Version: 1.0 To: "linux-btrfs@vger.kernel.org" Subject: Re: enquiry about autodefrag option References: <50570652.4060200@gmail.com> In-Reply-To: <50570652.4060200@gmail.com> Content-Type: text/plain; charset=UTF-8 Sender: linux-btrfs-owner@vger.kernel.org List-ID: can anybody helps? On 09/17/2012 07:15 PM, ching wrote: > I am testing btrfs for long-term storage and backup, and i would like > to know more about "autodefrag" option: > > 1. Will "autodefrag" option benefit ssd? > > My understanding is: > > autodrag -> number of extent decrease -> metadata decrease -> a > "healthier" filesystem in the long run > > (P.S. I am aware that autodefrag will introduce extra write I/O) > > 2. AFAIK, "autodefrag" detects small random writes into files and > queues them up for an automatic defrag process, so the filesystem will > defragment itself while it's used. > > If the system reboot/crash/remount-ro, will the autodefrag process > continue after resume? > >