From: Eric Sandeen Subject: how to scale root-reserved space going forward... Date: Sun, 01 Mar 2009 16:22:54 -0600 Message-ID: <49AB0ABE.1030009@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit To: ext4 development Return-path: Received: from mx2.redhat.com ([66.187.237.31]:38004 "EHLO mx2.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751202AbZCAWW6 (ORCPT ); Sun, 1 Mar 2009 17:22:58 -0500 Received: from int-mx2.corp.redhat.com (int-mx2.corp.redhat.com [172.16.27.26]) by mx2.redhat.com (8.13.8/8.13.8) with ESMTP id n21MMumq012556 for ; Sun, 1 Mar 2009 17:22:56 -0500 Received: from ns3.rdu.redhat.com (ns3.rdu.redhat.com [10.11.255.199]) by int-mx2.corp.redhat.com (8.13.1/8.13.1) with ESMTP id n21MMv1M007961 for ; Sun, 1 Mar 2009 17:22:57 -0500 Received: from liberator.sandeen.net (sebastian-int.corp.redhat.com [172.16.52.221]) by ns3.rdu.redhat.com (8.13.8/8.13.8) with ESMTP id n21MMtHC023798 for ; Sun, 1 Mar 2009 17:22:56 -0500 Sender: linux-ext4-owner@vger.kernel.org List-ID: 5% of a 16T filesystem is getting a little crazy from the point of view of "root-reserved" - 800G! But I think the original reason for this reserved space was actually as an allocator cushion; letting root gain access to it was just a safety-valve for that. Now that we have a completely different allocator in ext4, and potentially much larger filesystems, I think we need to revisit how much is held back, and for what reason. Any thoughts on a reasonable way to scale this reservation (or, just for discussion - if it's even needed at all today for ext4?) -Eric