From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from smtp-32-i2.italiaonline.it ([212.48.25.202]:36502 "EHLO smtp-32.italiaonline.it" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1754214AbbAGVDB (ORCPT ); Wed, 7 Jan 2015 16:03:01 -0500 Message-ID: <54AD9F85.1010608@inwind.it> Date: Wed, 07 Jan 2015 22:05:09 +0100 From: Goffredo Baroncelli Reply-To: kreijack@inwind.it MIME-Version: 1.0 To: Josef Bacik , Lennart Poettering , linux-btrfs@vger.kernel.org Subject: Re: price to pay for nocow file bit? References: <20150107174315.GA21865@gardel-login> <54AD929E.608@fb.com> In-Reply-To: <54AD929E.608@fb.com> Content-Type: text/plain; charset=windows-1252 Sender: linux-btrfs-owner@vger.kernel.org List-ID: > >> I am trying to understand the pros and cons of turning this bit >> on, before I can make this change. So far I see one big pro, but I >> wonder if there's any major con I should think about? >> > > Nope there's no real con other than you don't get csums, but that > doesn't really matter for you. Thanks, In a btrfs-raid setup, in case of a corrupted sector, is BTRFS able to rebuild the sector ? I suppose no; if so this has to be add to the cons I think. >>From my tests [1][2] I was unable to get bigger difference between doing a defrag and setting chattr -C the log directory. Did you get other results, if so I am interested to know more. BR G.Baroncelli [1] http://kreijack.blogspot.it/2014/06/btrfs-and-systemd-journal.html [2] http://lists.freedesktop.org/archives/systemd-devel/2014-June/020141.html