From owner-freebsd-fs@freebsd.org Fri Aug 23 18:26:43 2019 Return-Path: Delivered-To: freebsd-fs@mailman.nyi.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1]) by mailman.nyi.freebsd.org (Postfix) with ESMTP id 4E738CB563 for ; Fri, 23 Aug 2019 18:26:43 +0000 (UTC) (envelope-from matthew.ahrens@delphix.com) Received: from mail-vs1-xe41.google.com (mail-vs1-xe41.google.com [IPv6:2607:f8b0:4864:20::e41]) (using TLSv1.3 with cipher TLS_AES_128_GCM_SHA256 (128/128 bits) server-signature RSA-PSS (4096 bits) client-signature RSA-PSS (2048 bits) client-digest SHA256) (Client CN "smtp.gmail.com", Issuer "GTS CA 1O1" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id 46FVGp4YKvz43qm for ; Fri, 23 Aug 2019 18:26:42 +0000 (UTC) (envelope-from matthew.ahrens@delphix.com) Received: by mail-vs1-xe41.google.com with SMTP id y16so6862835vsc.3 for ; Fri, 23 Aug 2019 11:26:42 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=delphix.com; s=google; h=mime-version:references:in-reply-to:from:date:message-id:subject:to; bh=p61fMSEdFBokvj/3uq6VpZ3q8e7gQs6isff/2r/ti1w=; b=aXcw8eEJ+YcycnUXUnBElWEWt6DvMgHQW1GNUibjyBr+a1Mhlsl5LLByZ65Uxtg4hP fWaUvhkUE9l3RWtkgQb2v2A90YAt5BT64nGDfn9sow9oCsIqc2+45ZMUe9vgBCYZBmBO V+v7G3BnqLKoKpr1lySVg9P9aJlPbxsr3NQ2g= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to; bh=p61fMSEdFBokvj/3uq6VpZ3q8e7gQs6isff/2r/ti1w=; b=JyrRyJkfUPTJqBlWxWqiEMuTkn2+NzG4uqPdVkxdCVP14RTXkgVsHblwyxW13PCQOy 75FxCcca7bAlU6SHeQCCZkszF5uE0FbXrNB5mfTcn3Y0o/+l2puZ6u5bOZ57w5EZIPZD BB02D8e35LH1AfDuu2iyUMMVx/4B1PXEfnfvSa95vXhFs7q5meWQV0bNA/8xLENRE0jY xFJOpxeKzShADVX5D3UyBlBJWc3n3/I+Ic1IcYtOYENdCH/+gXBkLRXtI1ipm5gigFot aWuxQx//NmDA/O5qKqyXW+66pvuiqqCI1U7WjOKqMdPhTzw8RRD/Dz68lr3Rkol3tfex Kudg== X-Gm-Message-State: APjAAAW39yIE/MDlbN4H5Kz+E0cgw9YJ9fh1ONIPkOGT0EOPBrCIGiAE Oec7YhEEaJVyT8PeOhQHA7Gzms725mlFDZ4V53Xaj8emUso= X-Google-Smtp-Source: APXvYqxYJxniMzLbSx4gKcGlrch+7wgZY7ypODFYuN+kXVz6wygD+ucfSg6V7VzQizRcQ/yqw2ZR6yU98bDGRRIRX8k= X-Received: by 2002:a67:e45a:: with SMTP id n26mr3604523vsm.94.1566584800662; Fri, 23 Aug 2019 11:26:40 -0700 (PDT) MIME-Version: 1.0 References: In-Reply-To: From: Matthew Ahrens Date: Fri, 23 Aug 2019 11:26:28 -0700 Message-ID: Subject: Re: August OpenZFS Leadership Meeting To: developer , illumos-zfs , zfs-devel@list.zfsonlinux.org, zfs-devel@freebsd.org, freebsd-fs , zfs-discuss X-Rspamd-Queue-Id: 46FVGp4YKvz43qm X-Spamd-Bar: --- Authentication-Results: mx1.freebsd.org; dkim=pass header.d=delphix.com header.s=google header.b=aXcw8eEJ; dmarc=pass (policy=none) header.from=delphix.com; spf=pass (mx1.freebsd.org: domain of matthew.ahrens@delphix.com designates 2607:f8b0:4864:20::e41 as permitted sender) smtp.mailfrom=matthew.ahrens@delphix.com X-Spamd-Result: default: False [-3.20 / 15.00]; ARC_NA(0.00)[]; NEURAL_HAM_MEDIUM(-1.00)[-1.000,0]; R_DKIM_ALLOW(-0.20)[delphix.com:s=google]; FROM_HAS_DN(0.00)[]; TO_DN_SOME(0.00)[]; R_SPF_ALLOW(-0.20)[+ip6:2607:f8b0:4000::/36:c]; NEURAL_HAM_LONG(-1.00)[-1.000,0]; MIME_GOOD(-0.10)[multipart/alternative,text/plain]; PREVIOUSLY_DELIVERED(0.00)[freebsd-fs@freebsd.org]; URI_COUNT_ODD(1.00)[9]; RCPT_COUNT_FIVE(0.00)[6]; TO_MATCH_ENVRCPT_SOME(0.00)[]; DKIM_TRACE(0.00)[delphix.com:+]; DMARC_POLICY_ALLOW(-0.50)[delphix.com,none]; RCVD_IN_DNSWL_NONE(0.00)[1.4.e.0.0.0.0.0.0.0.0.0.0.0.0.0.0.2.0.0.4.6.8.4.0.b.8.f.7.0.6.2.list.dnswl.org : 127.0.5.0]; NEURAL_HAM_SHORT(-0.98)[-0.980,0]; FORGED_SENDER(0.30)[mahrens@delphix.com,matthew.ahrens@delphix.com]; MIME_TRACE(0.00)[0:+,1:+,2:~]; IP_SCORE(-0.52)[ip: (2.68), ipnet: 2607:f8b0::/32(-2.88), asn: 15169(-2.34), country: US(-0.05)]; ASN(0.00)[asn:15169, ipnet:2607:f8b0::/32, country:US]; FROM_NEQ_ENVFROM(0.00)[mahrens@delphix.com,matthew.ahrens@delphix.com]; RCVD_TLS_ALL(0.00)[]; RCVD_COUNT_TWO(0.00)[2] Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable X-Content-Filtered-By: Mailman/MimeDel 2.1.29 X-BeenThere: freebsd-fs@freebsd.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Filesystems List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 23 Aug 2019 18:26:43 -0000 Thanks to everyone who participated at this month's meeting. We discussed OpenZFS DevSummit talks; the Linux Plumbers Conference; 32-bit kernel atomic reads; zfs share -a on Linux; and dedup improvements. The video is available here: https://www.youtube.com/watch?v=3Dzl4CUMOIi18 Notes (thanks Karyn): - OpenZFS DevSummit talks (matt) - Lots of great talks so far, but there is still room. - If you forgot to submit a talk before yesterday=E2=80=99s deadline, p= lease reach out right away. Matt will announce selected speakers in 2 weeks= , so there is a small grace period. - Registration is open now, and Matt will publicize this more once we announce the speakers. - Linux Plumbers conf (Serapheim) - George WIlson and Serapheim will be at the Conference if you want to talk ZFS or Debugging the Linux Kernel - If so, please reach out so the ZFS folks can meet up and talk about all things ZFS. - OpenZFS on 32-bit architectures (relevant for FreeBSD, Linux, =E2=80=A6)= : plain reads of 64-bit =E2=80=9Catomics=E2=80=9D (Andriy) - Issue discovered: We use atomic operations to modify 64-bit values that we treat as atomic, but to read them we use plain C assignment operations, which works ok for 64-bit platforms, but not for 32-bit. Those plain reads are implemented as 2 instructions there (32-bit), which i= s incorrect. - At this point it is mostly theoretical (its is rare to hit a write while crossing the 32-bit boundary) but it is still a valid concern. - The code paths are not very critical - mostly stats that we send to user space. - Proposal for discussion: Should we introduce some kind of format wrappers for those operations? - Paul Dagnelie: Has done some similar work for the SPL back in the day and this should be straightforward. - Question: How many 32-bit platforms do we actually care for at this point? - Andriy: Have heard of a few 32-bit Intel users out there - Tom Caputi: Has some experience for compile-time checks for structures of these nature. - It seems like people are for it. Andriy will first talk with FreeBSD developers, figure out how they want to proceed, and try to propose designs common for all platforms. - zfs share -a (George) - Issue: Stale file handles using zfs share -a and the sharenfs property, by restarting or rebooting the nfs server. - The reason is that ZFS plugs into SystemD in a cumbersome/non-natural way. - NFS shares actually start before the ZFS service. Mountd responds to the client before the ZFS share is actually completed leading to the stale handles. - Hacky Approach: - Introduce a new component to zfs share. Instead of zfs share -a , zfs share -g (short for generate) - The idea is to add ZFS logic that ties it closer to NFS - Change of dependency ordering, zfs share -g generates the handles for NFS, before NFS, and NFS consumes those generated handles. - Cons: A bit hacky for now - Pros: Simple and fast - Plan: To do more redesign on top of this for a cleaner solution - Others that have similar issues with George/Delphix feel free to reach out. - Tom Caputi: Datto had issues with NFS in the past, and don't use sharenfs, but they are interested on having control over th= is functionality - Allan Jude: Seems like FreeBSD already does something similar, so there may be some convergence of goals. - Submitted this as lightning talk at the Dev Summit - Anyone interested in working on implementing Matt=E2=80=99s ideas for de= dup ceiling and on disk format log ( http://open-zfs.org/w/images/8/8d/ZFS_dedup.pdf) please contact allan@klarasystems.com to discuss. (Allan) - Problems using the feature for Terabytes of data due to known memory issues - There is budget for a contract to implement the limit of the size of the DDT proposed during one of the past Dev Summits - Feel free to reach out if you are interested in undertaking that work On Mon, Aug 19, 2019 at 12:56 PM Matthew Ahrens wrote= : > The next OpenZFS Leadership meeting will be held tomorrow, August 20, > 1pm-2pm Pacific time. > > Everyone is welcome to attend and participate, and we will try to keep th= e > meeting on agenda and on time. The meetings will be held online via Zoom= , > and recorded and posted to the website and YouTube after the meeting. > > The agenda for the meeting will be a discussion of the projects listed in > the agenda doc. > > For more information and details on how to attend, as well as notes and > video from the previous meeting, please see the agenda document: > > > https://docs.google.com/document/d/1w2jv2XVYFmBVvG1EGf-9A5HBVsjAYoLIFZAnW= HhV-BM/edit > > --matt >