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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 1044DC433F5 for ; Wed, 6 Apr 2022 10:30:46 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1346862AbiDFKcm (ORCPT ); Wed, 6 Apr 2022 06:32:42 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:53256 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230168AbiDFKbM (ORCPT ); Wed, 6 Apr 2022 06:31:12 -0400 Received: from wout3-smtp.messagingengine.com (wout3-smtp.messagingengine.com [64.147.123.19]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id AA263478001 for ; Tue, 5 Apr 2022 23:55:12 -0700 (PDT) Received: from compute1.internal (compute1.nyi.internal [10.202.2.41]) by mailout.west.internal (Postfix) with ESMTP id 25DD33200F9C for ; Wed, 6 Apr 2022 02:55:09 -0400 (EDT) Received: from mailfrontend2 ([10.202.2.163]) by compute1.internal (MEProxy); Wed, 06 Apr 2022 02:55:09 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d= messagingengine.com; h=cc:content-type:date:date:from:from :in-reply-to:message-id:mime-version:reply-to:sender:subject :subject:to:to:x-me-proxy:x-me-proxy:x-me-sender:x-me-sender :x-sasl-enc; s=fm3; bh=O0j133bChIeunoa1tyDMq53BpQIToB5MBoZsIqo3C iE=; b=U8mhkmlIe1yQZHL7tVL9FiiCPC5V1j0StS1hLw2Y4qZmH4JQG38tE/wvE PqSlk0bGDcKXoYihvYMNZr9cXij47vOSGvvpWBI+3BAj6ObjilunXJvrdxSF9fxY qtdEWNVxz0rm24HglRR0v2xwg+DJ9KzJhAQoizzmIEKILVyeHHQJ0AHH5ifQHBu3 6nFPdsOsHGZU/jjlzhVdk27QK/spWqhL6r629hye3/yQbqZMW9atwnsDAK4+lBbN v3cD+KWy/9Z0o9UQJmv3q6RFUO2VX3aVlNYc/ZC2PAGD74Z8LvW1I3RqoB0njr4E zt9otEjjJEHSvkQlbWuz/IcAk5d8g== X-ME-Sender: X-ME-Received: X-ME-Proxy-Cause: gggruggvucftvghtrhhoucdtuddrgedvvddrudejhedgudduudcutefuodetggdotefrod ftvfcurfhrohhfihhlvgemucfhrghsthforghilhdpqfgfvfdpuffrtefokffrpgfnqfgh necuuegrihhlohhuthemuceftddtnecunecujfgurhepfffhvffukfggtggusehgtderre dttddvnecuhfhrohhmpeffvghmihcuofgrrhhivgcuqfgsvghnohhurhcuoeguvghmihes ihhnvhhishhisghlvghthhhinhhgshhlrggsrdgtohhmqeenucggtffrrghtthgvrhhnpe dujefgjeeggeelhfevkeeltdekvdeuhfetiefffefhkeehhfevhefhkefgudegkeenucev lhhushhtvghrufhiiigvpedtnecurfgrrhgrmhepmhgrihhlfhhrohhmpeguvghmihesih hnvhhishhisghlvghthhhinhhgshhlrggsrdgtohhm X-ME-Proxy: Received: by mail.messagingengine.com (Postfix) with ESMTPA for ; Wed, 6 Apr 2022 02:55:08 -0400 (EDT) Date: Wed, 6 Apr 2022 02:55:04 -0400 From: Demi Marie Obenour To: linux-bcachefs@vger.kernel.org Subject: Comparison to ZFS and BTRFS Message-ID: MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="D2e4TZ+bMlesmL7Z" Content-Disposition: inline Precedence: bulk List-ID: X-Mailing-List: linux-bcachefs@vger.kernel.org --D2e4TZ+bMlesmL7Z Content-Type: text/plain; protected-headers=v1; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable Date: Wed, 6 Apr 2022 02:55:04 -0400 From: Demi Marie Obenour To: linux-bcachefs@vger.kernel.org Subject: Comparison to ZFS and BTRFS How does bcachefs manage to outperform ZFS and BTRFS? Obviously being licensed under GPL-compatible terms is an advantage for inclusion in Linux, but I am more interested in the technical aspects. - How does bcachefs avoid the nasty performance pitfalls that plague BTRFS? Are VM disks and databases on bcachefs fast? - How does bcachefs avoid the dreaded RAID write hole?=20 - How does an O_DIRECT loop device on bcachefs compare to a zvol on ZFS? - Is there a good description of the bcachefs on-disk format anywhere? - What are the internal abstraction layers used in bcachefs? Is it a key-value store with a filesystem on top of it, the way ZFS is? - Is it possible to shrink a bcachefs filesystem? Does bcachefs have any restrictions regarding the size of disks in a pool, or can I just throw a bunch of varying-size disks at bcachefs and have it spread the data around automatically to provide the level of redundancy I want? - Can bcachefs use faster storage as a cache for slower storage, or otherwise move data around based on usage patterns? - Can bcachefs saturate your typical NVMe drive on realistic workloads? Can it do so with encryption enabled? - Is support for swap files on bcachefs planned? That would require being able to perform O_DIRECT asynchronous writes without any memory allocations. - Is bcachefs being used in production anywhere? --=20 Sincerely, Demi Marie Obenour (she/her/hers) Invisible Things Lab --D2e4TZ+bMlesmL7Z Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQIzBAEBCAAdFiEEdodNnxM2uiJZBxxxsoi1X/+cIsEFAmJNOUoACgkQsoi1X/+c IsEgzBAAhMHiSh00IdNBkkSUR4WhtpZThvbXywneb0kMjtVAJOxNMxq3GewJa5rV 2WKeelfPr1EybkGNd8MmWYEAXGP0E0QCEx6q07IqLE2dQsnVMTuATn/M5upcBKJM b9zTIlJkf/wYzoMO4EA+mIJ5tVeWyzEceUKKD5PDLhket1sYSMXgL3Vbc8wtEXx5 MVDwJnOVhDGoprmTyrjpfeej2pXebsVBfhfOqhZk9UyVXJ/IKvyHK12TQeUXnwAc PhfUFtJiUatkVYGc6LNmnfCV0XxPGB+YjCKJ7LJMJGcp3k16xB4nf9QCSqM5xa+s vEGvFYiVJEZck7Eo93I7D7t7FIHUmAt4v7YpPRKukvOtbFM4WWskRzU88nilAmz8 nn4Lc3etFPOT3sa8rTQhQYk5el5PHPwEEC7KnDyRDDhaCnLBgG63DJ8hO6xJwTGi yTz5ksmiPsjYL1vcf2MTa6N0ZQwnB3y8fURjbSHZL9ZSn5BFcaaGWCASdy9SrY4N b2ISKhBF5dF8Xx/Pil3WaixYE32rS9eW5Xi6IapD9yNqOc2rNSw8ALQGDA1TUgtB 4zjkUWlBBYyjJkfqQAwMvfyxDCW/dUJd6oJVa6BWw6TghJaCJnA3hP6fThl85r7K v86aP+r/eu2tyhSmMcot9pxfgcNKT3y2Wr+qCfsUw2Q0D5fmWmg= =OGLK -----END PGP SIGNATURE----- --D2e4TZ+bMlesmL7Z--