From mboxrd@z Thu Jan 1 00:00:00 1970 From: Brad Campbell Subject: "Benchmarks" Date: Sat, 22 Oct 2011 08:29:02 +0800 Message-ID: <4EA20E4E.8050402@fnarfbargle.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: Sender: linux-bcache-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: linux-bcache-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-Id: linux-bcache@vger.kernel.org I use the term loosely. This is with the raw drive being a Maxtor MaxlineII 250GB 7200RPM SATA unit. It's about a 2004 vintage with over 30,000 hours on it. Slow and steady. The Cache device is an OCZ Vertex Plus 120GB Unit. Not all that fast or clever. The Cache has writeback enabled and is formatted with -w512 so that direct IO worked as previously discussed. The benchmark is conducted inside an XP VM running under KVM. The device is a qcow2 backing file formatted NTFS. I ran the test multiple times without the cache until the numbers stabilised (the backing file was being expanded as required) http://www.fnarfbargle.com/private/111022_bcache/Without_Cache.png http://www.fnarfbargle.com/private/111022_bcache/With_Cache.png As expected a significant improvement in random small I/O. The VM is far more responsive with the cache.