From owner-freebsd-stable@freebsd.org Thu Sep 22 14:48:36 2016 Return-Path: Delivered-To: freebsd-stable@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 0D04BBE5464; Thu, 22 Sep 2016 14:48:36 +0000 (UTC) (envelope-from dweimer@dweimer.net) Received: from webmail.dweimer.net (24-240-198-188.static.stls.mo.charter.com [24.240.198.188]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client did not present a certificate) by mx1.freebsd.org (Postfix) with ESMTPS id D2668EC4; Thu, 22 Sep 2016 14:48:35 +0000 (UTC) (envelope-from dweimer@dweimer.net) Received: from webmail.dweimer.local (localhost [10.9.5.2]) by webmail.dweimer.net (8.15.2/8.15.2) with ESMTPS id u8MEmSs2004461 (version=TLSv1.2 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=NO); Thu, 22 Sep 2016 09:48:28 -0500 (CDT) (envelope-from dweimer@dweimer.net) Received: (from www@localhost) by webmail.dweimer.local (8.15.2/8.15.2/Submit) id u8MEmSDJ004460; Thu, 22 Sep 2016 09:48:28 -0500 (CDT) (envelope-from dweimer@dweimer.net) X-Authentication-Warning: webmail.dweimer.local: www set sender to dweimer@dweimer.net using -f To: Slawa Olhovchenkov Subject: Re: zvol clone diffs MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII; format=flowed Content-Transfer-Encoding: 7bit Date: Thu, 22 Sep 2016 09:48:28 -0500 From: "Dean E. Weimer" Cc: "Eugene M. Zheganin" , freebsd-stable@freebsd.org, owner-freebsd-stable@freebsd.org Organization: dweimer.net Reply-To: dweimer@dweimer.net Mail-Reply-To: dweimer@dweimer.net In-Reply-To: <20160922143832.GJ2960@zxy.spb.ru> References: <57E3C705.2010702@norma.perm.ru> <20160922143832.GJ2960@zxy.spb.ru> Message-ID: X-Sender: dweimer@dweimer.net User-Agent: Roundcube Webmail/1.2.1 X-BeenThere: freebsd-stable@freebsd.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: Production branch of FreeBSD source code List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 22 Sep 2016 14:48:36 -0000 On 2016-09-22 9:38 am, Slawa Olhovchenkov wrote: > On Thu, Sep 22, 2016 at 04:56:53PM +0500, Eugene M. Zheganin wrote: > >> Hi. >> >> I should mention from the start that this is a question about an >> engineering task, not a question about FreeBSD issue. >> >> I have a set of zvol clones that I redistribute over iSCSI. Several >> Windows VMs use these clones as disks via their embedded iSCSI >> initiators (each clone represents a disk with an NTFS partition, is >> imported as a "foreign" disk and functions just fine). From my >> opinion, >> they should not have any need to do additional writes on these clones >> (each VM should only read data, from my point of view). But zfs shows >> they do, and sometimes they write a lot of data, so clearly facts and >> expactations differ a lot - obviously I didn't take something into >> accounting. > > May be atime like on NTFS? > > http://serverfault.com/questions/33932/how-do-you-disable-the-last-accessed-attribute-on-ntfs-windows I would recommend using the windows Diskpart command and settings the volumes attribute to read only, this will force the NTFS volume to be readonly and shouldn't allow changes to be saved. -- Thanks, Dean E. Weimer http://www.dweimer.net/