From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from vs2.lukas-pirl.de ([5.45.100.90]:35184 "EHLO pim.lukas-pirl.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753448AbbKZXzD (ORCPT ); Thu, 26 Nov 2015 18:55:03 -0500 Received: from [192.168.1.5] (unknown [119.224.19.150]) by pim.lukas-pirl.de (Postfix) with ESMTPSA id 2759220BA015 for ; Thu, 26 Nov 2015 23:55:00 +0000 (UTC) From: Lukas Pirl Subject: implications of mixed mode To: linux-btrfs@vger.kernel.org Message-ID: <56579BD1.4030401@lukas-pirl.de> Date: Fri, 27 Nov 2015 12:54:57 +1300 MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Sender: linux-btrfs-owner@vger.kernel.org List-ID: Dear list, if a larger RAID file system (say disk space of 8 TB in total) is created in mixed mode, what are the implications? >>From reading the mailing list and the Wiki, I can think of the following: + less hassle with "false positive" ENOSPC - data and metadata have to have the same replication level forever (e.g. RAID 1) - higher fragmentation (does this reduce with no(dir)atime?) -> more work for autodefrag Is that roughly what is to be expected? Any implications on recovery etc.? In the specific case, the file system usage is as follows: * data spread over ~20 subvolumes * snapshotted with various frequencies * compression is used * mostly archive storage * write once * read infrequently * ~500GB of daily rsync'ed system backup Thanks in advance, Lukas