From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wg0-f42.google.com ([74.125.82.42]:38987 "EHLO mail-wg0-f42.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752262AbaHMLGX (ORCPT ); Wed, 13 Aug 2014 07:06:23 -0400 Received: by mail-wg0-f42.google.com with SMTP id l18so10936297wgh.13 for ; Wed, 13 Aug 2014 04:06:22 -0700 (PDT) Message-ID: <53EB466A.40605@gmail.com> Date: Wed, 13 Aug 2014 14:05:14 +0300 From: Konstantinos Skarlatos MIME-Version: 1.0 To: David Pottage , 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> <53EB4581.8050104@chrestomanci.org> In-Reply-To: <53EB4581.8050104@chrestomanci.org> Content-Type: text/plain; charset=utf-8; format=flowed Sender: linux-btrfs-owner@vger.kernel.org List-ID: On 13/8/2014 2:01 μμ, David Pottage wrote: > > 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. > Yeah, thats one of the features I am waiting to get finished, because I already have 5 multi disk systems that i would prefer to migrate to RAID5/6 from RAID1/JBOD that they are now. I dont know what is the best sequencing, I just think that these are great patches/features and its a pity for them to languish. -- Konstantinos Skarlatos