From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from tartarus.angband.pl ([89.206.35.136]:43015 "EHLO tartarus.angband.pl" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751772AbcLHPbA (ORCPT ); Thu, 8 Dec 2016 10:31:00 -0500 Date: Thu, 8 Dec 2016 16:30:04 +0100 From: Adam Borowski To: David Sterba , linux-btrfs@vger.kernel.org Subject: Re: [PATCH] btrfs-progs: mkfs, balance convert: warn about RAID5/6 in fiery letters Message-ID: <20161208153004.GA31795@angband.pl> References: <20161128185153.14908-1-kilobyte@angband.pl> <20161130151245.GO12522@twin.jikos.cz> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii In-Reply-To: <20161130151245.GO12522@twin.jikos.cz> Sender: linux-btrfs-owner@vger.kernel.org List-ID: On Wed, Nov 30, 2016 at 04:12:46PM +0100, David Sterba wrote: > On Mon, Nov 28, 2016 at 07:51:53PM +0100, Adam Borowski wrote: > > People who don't frequent IRC nor the mailing list tend to believe RAID 5/6 > > are stable; this leads to data loss. Thus, let's do warn them. > > > > At this point, I think fiery letters that won't be missed are warranted. > > > > Kernel 4.9 and its -progs will be a part of LTS of multiple distributions, > > so leaving experimental features without a warning is inappropriate. > > I'm ok with adding the warning about raid56 feature, but I have some > comments to how it's implemented. > > Special case warning for the raid56 is ok, as it corresponds to the > 'mkfs_features' table where the missing value for 'safe' should lead to > a similar warning. This is planned to be more generic, so I just want to > make sure we can adjust it later without problems. There are at least two tools that can make a raid56: mkfs and balance convert. mkfs_features is used for the former but not for the latter. It doesn't appear to be machine-parseable as well (but that's a matter of editing the #define). Of course, making this generic is doable, I just don't know how do you plan to do that. Should I try to use mkfs_features somehow, or do it as a variant of the current patch for now? > The warning should go last, after the final summary (and respect verbosity > level). and for balance convert, before the output. > The colors seem a bit too much to me, red text or just emphasize > 'warning' would IMHO suffice. (in the paragraph before:) > If the message were not colored, I'd completely miss the warning. ... which means the color works! It _is_ intended to be offensive, so people can't possibly miss it. XFS uses something far more tame: black text on red background (\e[0;30;41m) but I want something that conveys the message appropriately. Obviously I'm not married to a particular color for this bikeshed, I just want a color that makes the neighbours complain :p English lacks a proper word for this, something akin to https://en.wiktionary.org/wiki/oczojebny -- u-boot problems can be solved with the help of your old SCSI manuals, the parts that deal with goat termination. You need a black-handled knife, and an appropriate set of candles (number and color matters). Or was it a silver-handled knife? Crap, need to look that up.