From mboxrd@z Thu Jan 1 00:00:00 1970 From: Phillip Susi Subject: Re: "not enough space" with "data raid0" Date: Wed, 28 Mar 2012 14:38:48 -0400 Message-ID: <4F735AB8.40301@ubuntu.com> References: <20120317121909.GB3172@carfax.org.uk> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed To: Hugo Mills , helmut@hullen.de, linux-btrfs@vger.kernel.org Return-path: In-Reply-To: <20120317121909.GB3172@carfax.org.uk> List-ID: On 3/17/2012 8:19 AM, Hugo Mills wrote: >> Where is the problem, how can I use the full space? > > You can't. btrfs requires RAID-0 to be at least two devices wide > (otherwise it's not striped at all, which is the point of RAID-0). If > you want to use the full capacity of both disks and don't care about > the performance gain from striping, use -d single (which is the > default). If you do care about the performance gain from striping, > then you're going to have to lose some usable space. So currently btrfs's concept of raid0 is "stripe across as many disks as possible, with a minimum of 2 disks". Is there any reason for that minimum? I don't see why it can't allow only one if that's the best it can manage.