From mboxrd@z Thu Jan 1 00:00:00 1970 From: Mike Subject: Move RBD Cache on clients from RAM to SSD. Date: Tue, 16 Jun 2015 10:59:40 +0300 Message-ID: <557FD76C.9070905@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Return-path: Received: from mail-lb0-f178.google.com ([209.85.217.178]:36105 "EHLO mail-lb0-f178.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753800AbbFPH7o (ORCPT ); Tue, 16 Jun 2015 03:59:44 -0400 Received: by lbbqq2 with SMTP id qq2so5458824lbb.3 for ; Tue, 16 Jun 2015 00:59:43 -0700 (PDT) Received: from mike.0xFFF ([212.34.43.122]) by mx.google.com with ESMTPSA id oq2sm57005lbb.34.2015.06.16.00.59.41 for (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Tue, 16 Jun 2015 00:59:42 -0700 (PDT) Sender: ceph-devel-owner@vger.kernel.org List-ID: To: ceph-devel@vger.kernel.org Hello. By now rbd_cache uses RAM, can we store cache on disk (SSD, SSD NVE)? In this way I look some benefits: * Don't waste a RAM for cache * Can make a big cache on SSD: 2-8Gb per cache * If you use Cache Tier - don't waste space on them * No need addition Ceph servers - use Compute with SSD. Yes it's for write-through and read-only cache strategies mostly. Any ideas? My be I am blind and this idea totally stupid?