From mboxrd@z Thu Jan 1 00:00:00 1970 From: Zenon Panoussis Subject: Object size Date: Thu, 28 Apr 2011 20:51:54 +0200 Message-ID: <4DB9B74A.10806@provocation.net> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Return-path: Received: from host-88-80-6-138.cust.prq.se ([88.80.6.138]:56698 "EHLO mail.nettheatre.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933239Ab1D1SwA (ORCPT ); Thu, 28 Apr 2011 14:52:00 -0400 Sender: ceph-devel-owner@vger.kernel.org List-ID: To: ceph-devel@vger.kernel.org Hi I'm trying to understand the relation between data size and actual disk usage. With replication x2 I am seeing a 1:4.4 ratio according to ceph (12222 MB data, 53579 MB used) and even more according to 'du -m' on the ext3 source of the ceph data (9791 MB instead of 12222 MB). What is the current default object size? A paper from 2004 by Sage et al speaks of 1 MB, a later one of 8 MB and http://diaspora.gen.nz/~rodgerd/archives/1219-Ceph.html says 4 MB. Is there a way to configure it? And is there any point in configuring it (I am using ceph to store millions of small files) or would it make no difference? Z