From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-ob0-f170.google.com ([209.85.214.170]:57258 "EHLO mail-ob0-f170.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751054AbaEGWjT (ORCPT ); Wed, 7 May 2014 18:39:19 -0400 Received: by mail-ob0-f170.google.com with SMTP id uy5so2055478obc.15 for ; Wed, 07 May 2014 15:39:19 -0700 (PDT) MIME-Version: 1.0 In-Reply-To: <20140507085240.GN10159@merlins.org> References: <20140507081840.GM10159@merlins.org> <20140507082941.GA19199@carfax.org.uk> <20140507085240.GN10159@merlins.org> Date: Wed, 7 May 2014 17:39:18 -0500 Message-ID: Subject: Re: raid0 vs single, and should we allow -mdup by default on SSDs? From: Mitch Harder To: Marc MERLIN Cc: Hugo Mills , Duncan <1i5t5.duncan@cox.net>, linux-btrfs Content-Type: text/plain; charset=UTF-8 Sender: linux-btrfs-owner@vger.kernel.org List-ID: On Wed, May 7, 2014 at 3:52 AM, Marc MERLIN wrote: > On Wed, May 07, 2014 at 09:29:41AM +0100, Hugo Mills wrote: >> On Wed, May 07, 2014 at 01:18:40AM -0700, Marc MERLIN wrote: >> > On Tue, May 06, 2014 at 07:39:12PM +0000, Duncan wrote: >> > > That appears to be a very good use of either -d raid0 or -d single, yes. >> > > And since you're apparently not streaming such high resolution video that >> > > you NEED the raid0, single does indeed give you a somewhat better chance >> > > at recovery. >> > >> > zoneminder saves 'video' as a stream of independent small jpegs, so I'm >> > good. Actually come to think of it they're so small that they probably >> > all ended up in the raid1 metadata. That also means that I'm not getting >> > twice the storage space like I planned to. Oh well... >> >> There's a mount option to change the threshold at which files are >> inlined in metadata: maxinline=. You could play with that for >> this particular use-case. > > Oh cool, thank you. > Since each non-inlined file will occupy a minimum of 4k, you may find that inlining will still save space even if it is duplicated. Even if they are duplicated in the metadata under RAID1, inlining a bunch of 256 byte files will still be more space efficient than storing them as regular files. But if most of the files are in the 2k-3k range, you may be more efficient to store them as files.