From mboxrd@z Thu Jan 1 00:00:00 1970 From: Wido den Hollander Subject: Re: Ideal hardware spec? Date: Sun, 26 Aug 2012 13:15:58 +0200 Message-ID: <503A056E.2020804@widodh.nl> References: <20120822135530.GB10015@csail.mit.edu> <5034E9F3.10001@widodh.nl> <20120822154615.GF10015@csail.mit.edu> <5035FF18.3030209@widodh.nl> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Return-path: Received: from smtp01.mail.pcextreme.nl ([109.72.87.137]:47194 "EHLO smtp01.mail.pcextreme.nl" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753505Ab2HZLPy (ORCPT ); Sun, 26 Aug 2012 07:15:54 -0400 In-Reply-To: Sender: ceph-devel-owner@vger.kernel.org List-ID: To: Andrey Korolyov Cc: "ceph-devel@vger.kernel.org" CC'ing this one back to the list. On 08/25/2012 09:58 PM, Andrey Korolyov wrote: >> >> They should be much more reliable than regular USB sticks due to their SLC >> memory. >> >> You could also take a look at these: >> http://www.transcend-info.com/industry/products_details.asp?CatNo=2&SerNo=14&ModNo=28&Func1No=1 >> >> > > Did you tried yet those or simular sticks for CEPH journal? Right now > I am using Intel 313`s, which is very fast and have durability/price > ratio a far higher than any imaginable MLC, but they occupying one HDD > slot which is a quite impractical. > No, I haven't tried, but I think it won't work. These kind of SLC chips don't do random writes that great, you'll probably get something like 4MB/sec in random writes. Bigger SSDs have more cells to spread the writes over, those small sticks don't. The Intel 3XX or 5XX serie should work just fine for journaling, I'd however recommend you change the Host Protected Area to ~50% of the available capacity to prevent write-degradation over time. Wido