From mboxrd@z Thu Jan 1 00:00:00 1970 From: Mike Almateia Subject: All-Flash Ceph cluster and journal Date: Thu, 19 Nov 2015 14:29:37 +0300 Message-ID: <564DB2A1.9080603@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Return-path: Received: from mail-lb0-f169.google.com ([209.85.217.169]:35992 "EHLO mail-lb0-f169.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932087AbbKSL3m (ORCPT ); Thu, 19 Nov 2015 06:29:42 -0500 Received: by lbblt2 with SMTP id lt2so41801334lbb.3 for ; Thu, 19 Nov 2015 03:29:40 -0800 (PST) Received: from [127.0.0.1] ([212.34.43.122]) by smtp.gmail.com with ESMTPSA id l128sm1142180lfe.27.2015.11.19.03.29.39 for (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Thu, 19 Nov 2015 03:29:40 -0800 (PST) Sender: ceph-devel-owner@vger.kernel.org List-ID: To: Ceph Development Hello. By now we have SSD disks with a great perfomance under O_DIRECT/O_SYNC flags (and we recomended to use they for journal). Why in a All-Flash type Ceph clusters we still use journal and them put a data into OSD? Why we can't just write a data into OSD with O_DIRECT/O_SYNC flags, without journal? Can we just switch off the journal functional for all-flash ceph clusters? -- Mike, runs.