From mboxrd@z Thu Jan 1 00:00:00 1970 From: Mark Nelson Subject: Re: Ceph Write Path Improvement Date: Thu, 03 Sep 2015 11:42:10 -0500 Message-ID: <55E87862.5060809@redhat.com> References: <755F6B91B3BE364F9BCA11EA3F9E0C6F2CE354DD@SACMBXIP01.sdcorp.global.sandisk.com> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Return-path: Received: from mx1.redhat.com ([209.132.183.28]:57303 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932569AbbICQmP (ORCPT ); Thu, 3 Sep 2015 12:42:15 -0400 In-Reply-To: Sender: ceph-devel-owner@vger.kernel.org List-ID: To: Robert LeBlanc , Somnath Roy Cc: ceph-devel On 09/03/2015 11:23 AM, Robert LeBlanc wrote: > -----BEGIN PGP SIGNED MESSAGE----- > Hash: SHA256 > > Somnath, > > I'm having a hard time with your slide deck. Am I understanding > correctly that the default Hammer install was performed on SSDs with > co-located journals, but the optimized code was performed on the same > SSDs but the journal was in NVRAM? If so I'm having a hard time > understanding how these tests can be comparable. I really like the > performance gains you are seeing, but I'm trying to understand how > much the optimized code alone helps performance. Hi Robert, We talked about this a bit at the weekly performance meeting. I think Somnath just hasn't gotten a chance to do those tests yet and is planning on doing them in the coming weeks. I believe he started out with hammer on the SSDs and then tried to figure out how to tweak things to make the NVRAM configuration perform better. Now he has to go back and retest the original configuration but with the new code. Mark