From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from [195.159.176.226] ([195.159.176.226]:34594 "EHLO blaine.gmane.org" rhost-flags-FAIL-FAIL-OK-OK) by vger.kernel.org with ESMTP id S1751308AbcK2FOb (ORCPT ); Tue, 29 Nov 2016 00:14:31 -0500 Received: from list by blaine.gmane.org with local (Exim 4.84_2) (envelope-from ) id 1cBakL-0004Yj-K7 for linux-btrfs@vger.kernel.org; Tue, 29 Nov 2016 06:14:25 +0100 To: linux-btrfs@vger.kernel.org From: Duncan <1i5t5.duncan@cox.net> Subject: Re: [Not TLS] Re: mount option nodatacow for VMs on SSD? Date: Tue, 29 Nov 2016 05:14:18 +0000 (UTC) Message-ID: References: <20161125082840.GA32711@rus.uni-stuttgart.de> <20161126112710.6aca8bac@jupiter.sol.kaishome.de> <20161128003829.GD15348@rus.uni-stuttgart.de> <2df2e8e6-5ac4-a9c0-70bc-406fd84e9784@cobb.uk.net> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-btrfs-owner@vger.kernel.org List-ID: Graham Cobb posted on Mon, 28 Nov 2016 09:49:33 +0000 as excerpted: > On 28/11/16 02:56, Duncan wrote: >> It should still be worth turning on autodefrag on an existing somewhat >> fragmented filesystem. It just might take some time to defrag files >> you do modify, and won't touch those you don't, which in some cases >> might make it worth defragging those manually. Or simply create new >> filesystems, mount them with autodefrag, and copy everything over so >> you're starting fresh, as I do. > > Could that "copy" be (a series of) send/receive, so that snapshots and > reflinks are preserved? Does autodefrag work in that case or does the > send/receive somehow override that and end up preserving the original > (fragmented) extent structure? Very good question that I don't know the answer to as I've not seen it discussed previously. (I'm not a dev, just a list regular and user of btrfs myself, and my personal use-case involves neither snapshots nor send/receive, so on those topics if I've not seen it covered previously either here or on the wiki, I won't know.) Someone else know? -- Duncan - List replies preferred. No HTML msgs. "Every nonfree program has a lord, a master -- and if you use the program, he is your master." Richard Stallman