From owner-freebsd-stable@FreeBSD.ORG Mon Sep 19 14:36:10 2011 Return-Path: Delivered-To: freebsd-stable@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 3D9051065670 for ; Mon, 19 Sep 2011 14:36:10 +0000 (UTC) (envelope-from rs@bytecamp.net) Received: from mail.bytecamp.net (mail.bytecamp.net [212.204.60.9]) by mx1.freebsd.org (Postfix) with ESMTP id 8C2618FC12 for ; Mon, 19 Sep 2011 14:36:09 +0000 (UTC) Received: (qmail 58180 invoked by uid 89); 19 Sep 2011 16:36:08 +0200 Received: from stella.bytecamp.net (HELO ?212.204.60.37?) (rs%bytecamp.net@212.204.60.37) by mail.bytecamp.net with CAMELLIA256-SHA encrypted SMTP; 19 Sep 2011 16:36:08 +0200 Message-ID: <4E775357.6020104@bytecamp.net> Date: Mon, 19 Sep 2011 16:36:07 +0200 From: Robert Schulze Organization: bytecamp GmbH User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.9.2.21) Gecko/20110831 Thunderbird/3.1.13 MIME-Version: 1.0 To: freebsd-stable@freebsd.org Content-Type: text/plain; charset=ISO-8859-15; format=flowed Content-Transfer-Encoding: 7bit Subject: change in io statistics since updating 8.2-STABLE X-BeenThere: freebsd-stable@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Production branch of FreeBSD source code List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 19 Sep 2011 14:36:10 -0000 Hello, like described in another thread, we recently updated a fileserver from 8.2-STABLE@2011-05-08 to 8.2-STABLE@2011-09-08 (amd64 both). ZPool is left at v14, the filesystems at version 3. Nothing in /boot/loader.conf or /etc/sysctl.conf has been changed. We now realize that r/w behaviour has changed on the whole pool. The l2arc devices (2 SSDs) have decreased in writes from average 10M/sec (peaks at 20 M/sec) to <5M/sec. On the other hand, reads on the disks (2x5 disks raidz2) have increased (nearly doubled on each disk). I suspect, that the cache is somewhat faulty or has become slow, and so ZFS decides to read data from main storage instead of the cache. Is there another explaination? Are there some defaults of sysctls which have been changed from May to September? with kind regards, Robert Schulze