DomainKey-Signature: a=rsa-sha1; c=nofws; d=sourceware.org; h=list-id
	:list-unsubscribe:list-subscribe:list-archive:list-post
	:list-help:sender:subject:to:references:from:message-id:date
	:mime-version:in-reply-to:content-type; q=dns; s=default; b=PZnR
	0LVT/SjPZ3Nzm+oKwV8EtlUOz+eaBbKF7tRt8MqyT8+cXpa/YJZWqzjv5ETaaAHb
	UekythB4lMJGY0G/IoBkl7tbEqsTfa1HDUe+JOJRSnmm2HYh9EQuGgwhxCJ1Zkvm
	SUzAf5Bl0ZV6cfhpyvgE3W7Z9g3SeOSAaFqxmTY=
Mailing-List: contact cygwin-help@cygwin.com; run by ezmlm
Sender: cygwin-owner@cygwin.com
Mail-Followup-To: cygwin@cygwin.com
Subject: Re: [cygwin] Re: Is a disk image created within dd "safe"?
To: cygwin@cygwin.com
References: <CA+imRYKfrvgVWUSh4=9tsF=QxjKGfPoiE-nRfVF7rbWO1v-b8A@mail.gmail.com> <CA+imRYLmnThTV-7=JQ_viDLk65HeO+2sUdxN+ThGkML6=k=iQw@mail.gmail.com> <55E772CF.4070807@redhat.com> <6F760D1B8B0E4196A66D0FE8765FE671@black7>
From: Eric Blake <eblake@redhat.com>
Openpgp: url=http://people.redhat.com/eblake/eblake.gpg
Message-ID: <55E77A91.5040203@redhat.com>
Date: Wed, 2 Sep 2015 16:39:13 -0600
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Thunderbird/38.1.0
MIME-Version: 1.0
In-Reply-To: <6F760D1B8B0E4196A66D0FE8765FE671@black7>
Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="iCsPtaPWuBV84cbteNw5DICTjKkcqw1e6"

--iCsPtaPWuBV84cbteNw5DICTjKkcqw1e6
Content-Type: text/plain; charset=utf-8
Content-Transfer-Encoding: quoted-printable

On 09/02/2015 04:23 PM, Jason Pyeron wrote:

>> There are various solutions that CAN capture an accurate=20
>> point-in-time disk snapshot.=20=20
>=20
> For cygwin/Windows use the Volume Shadow Service (VSS). I have used (XP)
> cygwin dd and rsync to take (clone) images from the VSS managed drive.

What's more, if you are running your Windows machine as a virtual
machine on top of qemu/kvm, you can install qemu-guest-agent into your
Windows setup, and set things up so that when the hypervisor wants to
take a snapshot of your guest, the guest-agent can coordinate with VSS
to make the point in time correspond to completely stable I/O (all
databases flushed and so forth, so the captured disk state is stable as
if you had gracefully powered off) rather than just a random state of
unflushed I/O (the disk state is as if you have yanked the power cord,
and may have missing transactions; hope your file system had decent
journaling if you wanted it to be consistent).

--=20
Eric Blake   eblake redhat com    +1-919-301-3266
Libvirt virtualization library http://libvirt.org


--iCsPtaPWuBV84cbteNw5DICTjKkcqw1e6
Content-Type: application/pgp-signature; name="signature.asc"
Content-Description: OpenPGP digital signature
Content-Disposition: attachment; filename="signature.asc"

-----BEGIN PGP SIGNATURE-----
Version: GnuPG v2
Comment: Public key at http://people.redhat.com/eblake/eblake.gpg
Comment: Using GnuPG with Thunderbird - http://www.enigmail.net/

iQEcBAEBCAAGBQJV53qRAAoJEKeha0olJ0NqNHQH+wRpXnM6RRC1mTyyWscGKg6c
jr2pm66xXZvqo29PwnTg5t96F1mxMeuPimtRZ0ohMSSqBNGscxMaZIWE2MLxFjpU
DJb0evGKK+gi4Tv8RqP7rnLEvNfxH48ztujqjOO9AyWUaYi+QHFz0IVbxZxfDn9f
i/xm4Oj6zsTRnxF9Babg+3ePp2URUjErCp3a3rz4FbSO/f+Por4IKVNDS1fNUx55
YwNFgstcW/QP5n28S2aD4cKXUHVUIe9QwganhQWWm9f9fSKmu+fPOZC6YKygRHB0
A1i6c57wx5PmK/lcT80HrFyON+HcOp8JeXJh9pTNMgrYS5cdosxcb/+ULSdRcG0=
=E7tr
-----END PGP SIGNATURE-----

--iCsPtaPWuBV84cbteNw5DICTjKkcqw1e6--