From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-2.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 5225AC07E9B for ; Tue, 20 Jul 2021 21:16:51 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 3F6F1610A7 for ; Tue, 20 Jul 2021 21:16:51 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234754AbhGTUf5 (ORCPT ); Tue, 20 Jul 2021 16:35:57 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:48512 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235238AbhGTU3F (ORCPT ); Tue, 20 Jul 2021 16:29:05 -0400 Received: from mail-qv1-xf35.google.com (mail-qv1-xf35.google.com [IPv6:2607:f8b0:4864:20::f35]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id D3C83C061767; Tue, 20 Jul 2021 14:09:40 -0700 (PDT) Received: by mail-qv1-xf35.google.com with SMTP id w2so10774380qvh.13; Tue, 20 Jul 2021 14:09:40 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to; bh=xAR3CTRKfX4JIGDK45soYaGIQy2kUk2KowfF/DLMbpk=; b=KUGvBKe3rD2Y5OgxqLkKudt79Vaw4+fQRksrrjy1vjAS+3FMWIH7efHlPpH1BUTcYY fLbWEYc2DHp5+Yn/jCHDREjoSS/n6C5sClfH0cQd3zjqzehRZE/Ziom2aR3d4/fd9nIA Vsvdq9CTn/Euig8jv1XJB563PEmhtLEF8iP8kRxRyOv+5m70BDkvBUzMcwYGZDR3Az4G /m47g4nmY1UC480D8UE2Tq03pYLQ67662WyYM/qf9sbFchhnIwS85dNTw1Lg8f8UIz8B iDSaesnWbzbrSosw70r/kubKyotZHYmyE2w1ByuvjgxHT5bPltgGl8dP9pf68ZrxYj1G i+/g== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to; bh=xAR3CTRKfX4JIGDK45soYaGIQy2kUk2KowfF/DLMbpk=; b=YXm6c/iV8wTE07IHSu3J1IK/Aj+FUKeTyJreF/8urHPWsbfw7xBj27fc5LeYUnRxav b0qYYNzfPdX+/ZqeJ7EEx5wIEZwlkxQsPSPqU4vrE+tSA9s7UvPqxSWGgORZ4s9ICIMB 2XJDbHZdcRK4NZBogWxpwOOS2iIqfEVKyh+Y50tF3VjY0YqgAypTQo7FYE16pbNC8Ehf xpdQwl096BPColqaM4lNU8O5TUuEoRkPe+/I5OWbx6mhoPAlGEKe4oTNMfLhZxwlHXku iQNCYgY+11/hZBq16rT0RSJ3VVVnh3DcBS773R6C/TjCdNt7Qjs8Yy/YTcTfLrnLqtj7 8GHA== X-Gm-Message-State: AOAM532Dh6cUT9TYxvb5FD9fDHTHJUpm3CGkuCcbHmXhXN4VVae3MV4Z Y9mxWVxpsRv3hBNJP/djoUjrv1wHn8jg X-Google-Smtp-Source: ABdhPJxrmetxGfx0Zh49bNjydeDdB5AUjMFV+eTdAwXlfDXqbbGyKI0rx6Wur1NSXcQPh0wu+2jdJg== X-Received: by 2002:ad4:56e4:: with SMTP id cr4mr32501653qvb.54.1626815379609; Tue, 20 Jul 2021 14:09:39 -0700 (PDT) Received: from moria.home.lan (c-73-219-103-14.hsd1.vt.comcast.net. [73.219.103.14]) by smtp.gmail.com with ESMTPSA id j7sm10284938qkd.21.2021.07.20.14.09.38 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 20 Jul 2021 14:09:38 -0700 (PDT) Date: Tue, 20 Jul 2021 17:09:35 -0400 From: Kent Overstreet To: Eric Wheeler Cc: linux-bcache@vger.kernel.org, linux-bcachefs@vger.kernel.org Subject: Re: bcachefs snapshots Message-ID: References: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-bcachefs@vger.kernel.org On Tue, Jul 20, 2021 at 01:28:33AM +0000, Eric Wheeler wrote: > Hi Kent, > > I read your bcachefs snapshots doc recently, it looks like you've put a > lot of thought into it. Is it ready for testing? > > We use a lot of btrfs snapshots of VM images but the performance is pretty > poor and I'm looking forward to trying out bcachefs snapshots when it is > ready to try out. > > We also have many dm-thin deployments backed by /dev/bcache0 volumes that > work quite well, but dm-thin meta is always an ongoing maintenance issue. > (Don't run out of dm-thin meta space or *boom*!) > > If bcachefs can replace dm-thin with loopback files (or even better, > native bcachefs devices!) then I look forward to getting beyond > dm-thin into something more scalable. It's not ready just yet - but the initial performance numbers are _extremely_ encouraging, I'll be posting more soon!