From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from smarthost01a.mail.zen.net.uk ([212.23.1.1]:52218 "EHLO smarthost01a.mail.zen.net.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751024AbaHMLBd (ORCPT ); Wed, 13 Aug 2014 07:01:33 -0400 Received: from [82.70.68.182] (helo=www.chrestomanci.org) by smarthost01a.mail.zen.net.uk with esmtps (TLS1.2:DHE_RSA_AES_256_CBC_SHA256:256) (Exim 4.80) (envelope-from ) id 1XHWJ8-000DL1-Uu for linux-btrfs@vger.kernel.org; Wed, 13 Aug 2014 11:01:31 +0000 Message-ID: <53EB4581.8050104@chrestomanci.org> Date: Wed, 13 Aug 2014 12:01:21 +0100 From: David Pottage MIME-Version: 1.0 To: Vimal A R , "linux-btrfs@vger.kernel.org" Subject: Re: Ideas for a feature implementation References: <1407698476.20187.YahooMailNeo@web192906.mail.sg3.yahoo.com> <53E9F3D6.9040502@gmail.com> In-Reply-To: <53E9F3D6.9040502@gmail.com> Content-Type: text/plain; charset=utf-8; format=flowed Sender: linux-btrfs-owner@vger.kernel.org List-ID: On 12/08/14 12:00, Konstantinos Skarlatos wrote: > Maybe help with Andrea Mazzoleni's New RAID library supporting up to > six parities? It seems to be a great feature for btrfs. > > https://www.mail-archive.com/linux-btrfs@vger.kernel.org/msg31735.html That would be very cool, but at present vanila RAID 5 or 6 does not work properly, so I think getting that fully working would be a better idea. (Unless it would make more sense to merge the whole lot into one bit of work where RAID 5 or 6 are just a special case of arbitrary parity level support). At present, you can write RAID 5 or 6 data, but if anything goes wrong, btrfs cannot use the parity information to help you get your data back, so in general you are better off with RAID 1 or 10. Also, I don't think I/O done in parallel so you get no speed advantage from having multiple discs either. -- David Pottage