From owner-freebsd-hackers@freebsd.org Sun Apr 29 18:34:08 2018 Return-Path: Delivered-To: freebsd-hackers@mailman.ysv.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1]) by mailman.ysv.freebsd.org (Postfix) with ESMTP id E877FFB4854 for ; Sun, 29 Apr 2018 18:34:07 +0000 (UTC) (envelope-from wlosh@bsdimp.com) Received: from mail-io0-x231.google.com (mail-io0-x231.google.com [IPv6:2607:f8b0:4001:c06::231]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (Client CN "smtp.gmail.com", Issuer "Google Internet Authority G2" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id 4954B7082D for ; Sun, 29 Apr 2018 18:34:07 +0000 (UTC) (envelope-from wlosh@bsdimp.com) Received: by mail-io0-x231.google.com with SMTP id e20-v6so7966803iof.4 for ; Sun, 29 Apr 2018 11:34:07 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=bsdimp-com.20150623.gappssmtp.com; s=20150623; h=mime-version:sender:in-reply-to:references:from:date:message-id :subject:to:cc; bh=BaNki7abp+a/BZuXxYzg6EGbIz9W1/HBg1D5jZGc7jI=; b=XR72VzL6S3vSDGEg4m0gSavWLjw6yqGBombQ48vv0Y7t7IrEfREIGB1qc2LrGeDKWM 4JkYunpxCtRhHvyinjUJbxryH6P1idVMzcbcmQ/VWZOwcNJmKRkqIN4TsBLJbIvzSMDE nIge6L0J+OhCxPdGwKKnLS7f0rZ4IwqZWpf5PiXbqSM+hvVwQtjkyUrWOsh9Q4e9sYBD ni/K7olkgR9ZhbmT3unxIRap4S0VCDKK6APyg+YRy2NeYgRNo9hpjlm+doDDmyqySwdT IlpEq7C6PPYlXXazlVimWSfngVoEhPfPZ5DKsuoix6pG1AxJtkUPDmFxuOZLPGUf4ZZh Xj6g== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:sender:in-reply-to:references:from :date:message-id:subject:to:cc; bh=BaNki7abp+a/BZuXxYzg6EGbIz9W1/HBg1D5jZGc7jI=; b=LTxb2ydtTA6hZisz29sr0CGXmwsNDest23wfWtHYWhiI1BEQJSczOsiCtFwxUs+zwf 61x4VeA6+o9lWYKElvfBdRhkzV4LcNnOsfftRpb+0+uYD43C7mPpuHy1h5koRPWf2MKe +FBt0r19HZm6sjzgnCDcUQKRHB7AiT3kK6FVIU43/tpWvotikFn3YNC/v4TGG3KGhCkG bxvtSWdJne9ePwrvtpR+XTCoh1nuP/w8j2LCs9do+czsmqiBegArMlaaEdwu0C7tKEMJ yRzebG0WIHn1KmomitzjUsH+bro91e7SwQVnm+ZKE7/Nn4r1/NO6XrYt8PgzQjVL+FVU Iv/A== X-Gm-Message-State: ALQs6tAUuSShmHN1mToAfs6z7witMmgVATanm1FZATTHIJvk+KcDzRu0 C0ajAihFdO7bPjUgHQqZkKvC3FA/PUfn5O7rMh3VPg== X-Google-Smtp-Source: AB8JxZow7PoPmhek7TqiAXS9wwOgfkLIBPTnKB2XIR75Z5k16nng4+aDNbhUE07HB+O78f8Nq9q7dPnAwhgiJDQed2Y= X-Received: by 2002:a6b:d404:: with SMTP id l4-v6mr10065025iog.37.1525026846533; Sun, 29 Apr 2018 11:34:06 -0700 (PDT) MIME-Version: 1.0 Sender: wlosh@bsdimp.com Received: by 2002:a4f:a65a:0:0:0:0:0 with HTTP; Sun, 29 Apr 2018 11:34:06 -0700 (PDT) X-Originating-IP: [2603:300b:6:5100:1052:acc7:f9de:2b6d] In-Reply-To: <5692d3b6-038e-4c4b-c5b6-b0f719b4ac38@digitaldaemon.com> References: <5f836c79-b379-f066-689b-1645e393c5e9@digiware.nl> <1645b168-4133-693c-2dd3-8e0606abb9c3@digiware.nl> <07576f68-f67e-3a22-7a50-ff261c9b3fff@digitaldaemon.com> <5692d3b6-038e-4c4b-c5b6-b0f719b4ac38@digitaldaemon.com> From: Warner Losh Date: Sun, 29 Apr 2018 12:34:06 -0600 X-Google-Sender-Auth: 2OHb_nsgMQX9zCbsizBr0zA17fE Message-ID: Subject: Re: Getting ZFS pools back. To: Jan Knepper Cc: Willem Jan Withagen , Alan Somers , FreeBSD Filesystems , FreeBSD Hackers , Richard Yao Content-Type: text/plain; charset="UTF-8" X-Content-Filtered-By: Mailman/MimeDel 2.1.25 X-BeenThere: freebsd-hackers@freebsd.org X-Mailman-Version: 2.1.25 Precedence: list List-Id: Technical Discussions relating to FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sun, 29 Apr 2018 18:34:08 -0000 On Sun, Apr 29, 2018 at 12:31 PM, Jan Knepper wrote: > However, most 11.x binaries work well enough to at least bootstrap / fix > problems if booted on a 10.x kernel due to targeted forward compatibility. > You shouldn't count on it for long, but it generally won't totally brick > your box. In the past, and I believe this is still true, they work well > enough to compile and install a new kernel after pulling sources. The 10.x > -> 11.x syscall changes are such that you should be fine. At least if you > are on UFS. > > However, the ZFS ioctls and such are in the bag of 'don't specifically > guarantee and also they change a lot' so that may be why you can't mount > ZFS by UUID. I've not checked to see if there's specifically an issue here > or not. The ZFS ABI is somewhat more fragile than other parts of the > system, so you may have issues here. > > If all else fails, you may be able to PXE boot an 11 kernel, or boot off a > USB memstick image to install a kernel. > > Generally, while we don't guarantee forward compatibility (running newer > binaries on older kernels), we've generally built enough forward compat so > that things work well enough to complete the upgrade. That's why you > haven't hit an issue in 18 years of upgrading. However, the velocity of > syscall additions has increased, and we've gone from fairly stable (stale?) > ABIs for UFS to a more dynamic one for ZFS where backwards compat is a bit > of a crap shoot and forward compat isn't really there at all. That's likely > why you've hit a speed bump here. > > I have not closely looked at the procedures outlined in /usr/src/UPDATING > for 11.x. But do I read correctly that performing a buildworld, > buildkernel, then installworld and reboot to update from 10.4 to 11.x does > not work? > No. That will work. If you always install a new kernel and reboot (especially across major releases) and then install the new binaries, you're safe. You won't get into a situation where new binaries are running on an old kernel. As far as I know that's not broken, even with the strange ABI issues I talk about. That's only when you're running 11.x binaries on a 10.x kernel, not the other way around. Warner