From owner-freebsd-hackers@freebsd.org Sun Apr 29 18:31:35 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 7E504FB46DC for ; Sun, 29 Apr 2018 18:31:35 +0000 (UTC) (envelope-from jan@digitaldaemon.com) Received: from digitaldaemon.com (digitaldaemon.com [162.217.114.50]) by mx1.freebsd.org (Postfix) with SMTP id 15BDD705BE for ; Sun, 29 Apr 2018 18:31:34 +0000 (UTC) (envelope-from jan@digitaldaemon.com) Received: (qmail 28614 invoked by uid 89); 29 Apr 2018 18:31:31 -0000 Received: from c-24-0-179-87.hsd1.nj.comcast.net (HELO iMac.local) (jan@digitaldaemon.com@24.0.179.87) by digitaldaemon.com with SMTP; 29 Apr 2018 18:31:31 -0000 Subject: Re: Getting ZFS pools back. To: Warner Losh Cc: Willem Jan Withagen , Alan Somers , FreeBSD Filesystems , FreeBSD Hackers , Richard Yao References: <5f836c79-b379-f066-689b-1645e393c5e9@digiware.nl> <1645b168-4133-693c-2dd3-8e0606abb9c3@digiware.nl> <07576f68-f67e-3a22-7a50-ff261c9b3fff@digitaldaemon.com> From: Jan Knepper Message-ID: <5692d3b6-038e-4c4b-c5b6-b0f719b4ac38@digitaldaemon.com> Date: Sun, 29 Apr 2018 14:31:30 -0400 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.12; rv:52.0) Gecko/20100101 Thunderbird/52.7.0 MIME-Version: 1.0 In-Reply-To: Content-Language: en-US Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit 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 18:31:35 -0000 On 04/29/2018 14:21, Warner Losh wrote: > On Sun, Apr 29, 2018 at 11:57 AM, Jan Knepper > wrote: > > On 04/29/2018 13:27, Willem Jan Withagen wrote: > > Trouble started when I installed (freebsd-update) 11.1 over a > running 10.4. Which is sort of scarry? > > This does sounds 'scary' as I am planning to do this in the (near) > future... > > Has anyone else experienced issues like this? > > Generally I do build the new system software on a running system, > but then go to single user mode to perform the actual install. > > I have done many upgrades like that over 18 or so years and never > seen or heard of an issue alike this. > > > 11.x binaries aren't guaranteed to work with a 10.x kernel. So that's > a bit of a problem. freebsd-update shouldn't have let you do that either. The process I have used so far is to svnup, build, reboot... > 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? Thanks! ManiaC++ Jan Knepper