From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wm0-f47.google.com ([74.125.82.47]:35940 "EHLO mail-wm0-f47.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751162AbbL2EFV (ORCPT ); Mon, 28 Dec 2015 23:05:21 -0500 Received: by mail-wm0-f47.google.com with SMTP id l65so21927821wmf.1 for ; Mon, 28 Dec 2015 20:05:21 -0800 (PST) Date: Mon, 28 Dec 2015 19:03:36 -0500 From: Sanidhya Solanki To: Christoph Anton Mitterer Cc: linux-btrfs@vger.kernel.org Subject: Re: [PATCH] BTRFS: Adds an option to select RAID Stripe size Message-ID: <20151228190336.59a3f440@gmail.com> In-Reply-To: <1451360528.7094.7.camel@scientia.net> References: <1451305451-31222-1-git-send-email-jpage.lkml@gmail.com> <1451341195.7094.0.camel@scientia.net> <20151228153801.6561feff@gmail.com> <1451352069.7094.3.camel@scientia.net> <20151228164333.2b8d8336@gmail.com> <1451360528.7094.7.camel@scientia.net> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Sender: linux-btrfs-owner@vger.kernel.org List-ID: On Tue, 29 Dec 2015 04:42:08 +0100 Christoph Anton Mitterer wrote: > On Mon, 2015-12-28 at 16:43 -0500, Sanidhya Solanki wrote: > May get even much more complicated, if reshaping (i.e. conversion from > one chunk size to another) should get implemented as well... That sounds like an absolutely ghastly idea. Lots of potential for mistakes and potential data loss. I take up the offer to implement such a feature. Only question is should it be in-place replacement or replace out to another disk or storage type. Will wait for comments on that question before implementing. > Sure :) > Being able to set the RAID chunk size makes AFAIU sense for every RAID > level, depending which IO patterns one has (i.e. even for RAID1). I do not understand this part. Is the stripe size not independent of the RAID type? To me it would seem that the filesystem just treats the RAID type as a means of duplicating (if in the case of a redundant RAID) or parallelizing data (in case of "R"AID 0), as opposed to the Stripe length, which is a measure of each logical block for the filesystem. Thanks.