From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-it0-f48.google.com ([209.85.214.48]:35412 "EHLO mail-it0-f48.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751579AbdGZMg7 (ORCPT ); Wed, 26 Jul 2017 08:36:59 -0400 Received: by mail-it0-f48.google.com with SMTP id h199so66196416ith.0 for ; Wed, 26 Jul 2017 05:36:58 -0700 (PDT) Subject: Re: btrfs raid assurance To: Hugo Mills , waxhead , =?UTF-8?Q?H=c3=a9rikz_Nawarro?= , linux-btrfs@vger.kernel.org References: <20170725134656.GL7140@carfax.org.uk> <20170725135146.GM7140@carfax.org.uk> <20170725135835.GN7140@carfax.org.uk> <20170725214505.GP7140@carfax.org.uk> <3ae7c0e5-ce84-cbc7-9e68-9e4df9aa4f18@gmail.com> <20170726122720.GQ7140@carfax.org.uk> From: "Austin S. Hemmelgarn" Message-ID: Date: Wed, 26 Jul 2017 08:36:54 -0400 MIME-Version: 1.0 In-Reply-To: <20170726122720.GQ7140@carfax.org.uk> Content-Type: text/plain; charset=windows-1252; format=flowed Sender: linux-btrfs-owner@vger.kernel.org List-ID: On 2017-07-26 08:27, Hugo Mills wrote: > On Wed, Jul 26, 2017 at 08:12:19AM -0400, Austin S. Hemmelgarn wrote: >> On 2017-07-25 17:45, Hugo Mills wrote: >>> On Tue, Jul 25, 2017 at 11:29:13PM +0200, waxhead wrote: >>>> >>>> >>>> Hugo Mills wrote: >>>>> >>>>>>> You can see about the disk usage in different scenarios with the >>>>>>> online tool at: >>>>>>> >>>>>>> http://carfax.org.uk/btrfs-usage/ >>>>>>> >>>>>>> Hugo. >>>>>>> >>>> As a side note, have you ever considered making this online tool >>>> (that should never go away just for the record) part of btrfs-progs >>>> e.g. a proper tool? I use it quite often (at least several timers >>>> per. month) and I would love for this to be a visual tool >>>> 'btrfs-space-calculator' would be a great name for it I think. >>>> >>>> Imagine how nice it would be to run.... >>>> >>>> btrfs-space-calculator -mraid1 -draid10 /dev/sda1 /dev/sdb1 >>>> /dev/sdc2 /dev/sdd2 /dev/sde3 for example and instantly get >>>> something similar to my example below (no accuracy intended) >>> >>> It's certainly a thought. I've already got the algorithm written >>> up. I'd have to resurrect my C skills, though, and it's a long way >>> down my list of things to do. :/ >>> >>> Also on the subject of this tool, I'd like to make it so that the >>> parameters get set in the URL, so that people can copy-paste the URL >>> of the settings they've got into IRC for discussion. However, that >>> would involve doing more JavaScript, which is possibly even lower down >>> my list of things to do than starting doing C again... > >> Is the core logic posted somewhere? Because if I have some time, I >> might write up a quick Python script to do this locally (it may not >> be as tightly integrated with the regular tools, but I can count on >> half a hand how many distros don't include Python by default). > > If it's going to be done in python, I might as well do it myself -- > I can do python with my eyes closed. It's just C and JS I'm rusty with. Same here ironically :) > > There is a write-up of the usable-space algorithm somewhere. I > wrote it up in detail (with pseudocode) in a mail on this list. I've > also got several pages of LaTeX somewhere where I tried and failed to > prove the correctness of the formula. I'll see if I can dig them out > this evening. It looks like the Message-ID for the one on the mailing list is <20160311221703.GJ17196@carfax.org.uk> I had forgotten that I'd archived that with the intent of actually doing something with it eventually...