From owner-freebsd-bugs@FreeBSD.ORG  Wed Nov 27 23:40:02 2013
Return-Path: <owner-freebsd-bugs@FreeBSD.ORG>
Delivered-To: freebsd-bugs@smarthost.ysv.freebsd.org
Received: from mx1.freebsd.org (mx1.freebsd.org
 [IPv6:2001:1900:2254:206a::19:1])
 (using TLSv1 with cipher ADH-AES256-SHA (256/256 bits))
 (No client certificate requested)
 by hub.freebsd.org (Postfix) with ESMTPS id 50D1C3E9
 for <freebsd-bugs@smarthost.ysv.freebsd.org>;
 Wed, 27 Nov 2013 23:40:02 +0000 (UTC)
Received: from freefall.freebsd.org (freefall.freebsd.org
 [IPv6:2001:1900:2254:206c::16:87])
 (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits))
 (No client certificate requested)
 by mx1.freebsd.org (Postfix) with ESMTPS id 3CF4F62A
 for <freebsd-bugs@smarthost.ysv.freebsd.org>;
 Wed, 27 Nov 2013 23:40:02 +0000 (UTC)
Received: from freefall.freebsd.org (localhost [127.0.0.1])
 by freefall.freebsd.org (8.14.7/8.14.7) with ESMTP id rARNe1U6004881
 for <freebsd-bugs@freefall.freebsd.org>; Wed, 27 Nov 2013 23:40:01 GMT
 (envelope-from gnats@freefall.freebsd.org)
Received: (from gnats@localhost)
 by freefall.freebsd.org (8.14.7/8.14.7/Submit) id rARNe1dA004880;
 Wed, 27 Nov 2013 23:40:01 GMT (envelope-from gnats)
Date: Wed, 27 Nov 2013 23:40:01 GMT
Message-Id: <201311272340.rARNe1dA004880@freefall.freebsd.org>
To: freebsd-bugs@FreeBSD.org
Cc: 
From: info@ITSMexpert.EU
Subject: Re: kern/184154: [cam] QUIRK: SYNC_CACHE not supported on IBM
 ServeRAID 8k
X-BeenThere: freebsd-bugs@freebsd.org
X-Mailman-Version: 2.1.16
Precedence: list
Reply-To: info@ITSMexpert.EU
List-Id: Bug reports <freebsd-bugs.freebsd.org>
List-Unsubscribe: <http://lists.freebsd.org/mailman/options/freebsd-bugs>,
 <mailto:freebsd-bugs-request@freebsd.org?subject=unsubscribe>
List-Archive: <http://lists.freebsd.org/pipermail/freebsd-bugs/>
List-Post: <mailto:freebsd-bugs@freebsd.org>
List-Help: <mailto:freebsd-bugs-request@freebsd.org?subject=help>
List-Subscribe: <http://lists.freebsd.org/mailman/listinfo/freebsd-bugs>,
 <mailto:freebsd-bugs-request@freebsd.org?subject=subscribe>
X-List-Received-Date: Wed, 27 Nov 2013 23:40:02 -0000

The following reply was made to PR kern/184154; it has been noted by GNATS.

From: info@ITSMexpert.EU
To: mjacob@freebsd.org, bug-followup@freebsd.org
Cc:  
Subject: Re: kern/184154: [cam] QUIRK: SYNC_CACHE not supported on IBM ServeRAID
 8k
Date: Thu, 28 Nov 2013 00:29:26 +0100

 Just attempt to mount a ZFS pool on six RDM disks caused writing 13 
 error messages for each disk (78 error messages together, five line in 
 dmesg each).
 The mount WAS NOT successful.
 
 ZFS uses SYNC_CACHE quite often (because of its principle), it can lead 
 into significant performance degradation (if mounted).
 
 I can not tolerate such behaviour in production environment handling 
 terabytes of archive data.
 
 I need to upgrade to 10.0 as soon as the STABLE version will be released.
 It seems I will have to patch and recompile kernel first. :-(
 
 On 27/11/2013 23:09, Matthew Jacob wrote:
 > Why do you think this is a serious error? All that the lack of this
 > command support does is cause the driver to be noisy. The device still
 > functions correctly, doesn't it?
 >
 > 10.X is frozen and won't be changed until after release.