From owner-freebsd-fs@freebsd.org Fri Feb 19 06:23:16 2016 Return-Path: Delivered-To: freebsd-fs@mailman.ysv.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) by mailman.ysv.freebsd.org (Postfix) with ESMTP id 54EF1AAD007 for ; Fri, 19 Feb 2016 06:23:16 +0000 (UTC) (envelope-from rpokala@mac.com) Received: from mr11p00im-asmtp004.me.com (mr11p00im-asmtp004.me.com [17.110.69.135]) (using TLSv1.2 with cipher DHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (Client did not present a certificate) by mx1.freebsd.org (Postfix) with ESMTPS id 42AE21C63 for ; Fri, 19 Feb 2016 06:23:16 +0000 (UTC) (envelope-from rpokala@mac.com) Received: from [172.20.10.3] (unknown [172.56.41.194]) by mr11p00im-asmtp004.me.com (Oracle Communications Messaging Server 7.0.5.36.0 64bit (built Sep 8 2015)) with ESMTPSA id <0O2S006U172PN730@mr11p00im-asmtp004.me.com> for freebsd-fs@freebsd.org; Fri, 19 Feb 2016 06:23:14 +0000 (GMT) X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10432:,, definitions=2016-02-19_05:,, signatures=0 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 spamscore=0 clxscore=1015 suspectscore=0 malwarescore=0 phishscore=0 adultscore=0 bulkscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1510270003 definitions=main-1602190088 User-Agent: Microsoft-MacOutlook/0.0.0.160109 Date: Thu, 18 Feb 2016 22:23:10 -0800 Subject: Re: Hours of tiny transfers at the end of a ZFS resilver? From: Ravi Pokala Sender: "Pokala, Ravi" To: "freebsd-fs@freebsd.org" Message-id: <75A39599-A668-4A2E-9956-98479A28930A@panasas.com> Thread-topic: Hours of tiny transfers at the end of a ZFS resilver? MIME-version: 1.0 Content-type: text/plain; charset=UTF-8 Content-transfer-encoding: 7bit X-BeenThere: freebsd-fs@freebsd.org X-Mailman-Version: 2.1.20 Precedence: list List-Id: Filesystems List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 19 Feb 2016 06:23:16 -0000 >Date: Tue, 16 Feb 2016 09:09:17 +0000 >From: Steven Hartland >To: freebsd-fs@freebsd.org >Subject: Re: Hours of tiny transfers at the end of a ZFS resilver? >Message-ID: <56C2E73D.2010405@multiplay.co.uk> >Content-Type: text/plain; charset=windows-1252; format=flowed > >This is 4k underlying, SSD's are by far and away the worst culprits for this. On the one hand, you're right - SSDs actually *do* lie about their 512n/AF-512e/AF-4Kn designation. On the other hand, SSD erase blocks - and even program blocks - are larger than 4KB, so neither AF-* designation would be correct anyway. And to some extent, it doesn't matter for SSDs, since everything is so heavily indirected anyway. -Ravi (rpokala@)