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Date: Thu, 22 Sep 2016 17:38:32 +0300
From: Slawa Olhovchenkov <slw@zxy.spb.ru>
To: "Eugene M. Zheganin" <emz@norma.perm.ru>
Cc: freebsd-stable@FreeBSD.org
Subject: Re: zvol clone diffs
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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