From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ian Pilcher Subject: Small chunk size read performance penalty Date: Sun, 18 Aug 2013 17:05:01 -0500 Message-ID: Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Return-path: Sender: linux-raid-owner@vger.kernel.org To: linux-raid@vger.kernel.org List-Id: linux-raid.ids Can anyone point me to a good explanation of the read performance impact of small (RAID-5 and RAID-6) chunk sizes? I understand why large chunks hurt write performance, but I haven't been able to reason through the small-chunk/read case, and my Interweb searches haven't really turned anything up. The "read penalty" is definitely there; I can see it in the test data from my NAS. I just don't understand *why* it's there. Thanks! -- ======================================================================== Ian Pilcher arequipeno@gmail.com Sometimes there's nothing left to do but crash and burn...or die trying. ========================================================================