From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jacob Broido Subject: Fwd: cow snapshot on cloop device Date: Wed, 24 Aug 2005 19:01:21 +0200 Message-ID: <6262291505082410015647272d@mail.gmail.com> References: <6262291505082404352d0a4dc2@mail.gmail.com> <200508241358.56758.kevcorry@us.ibm.com> <6262291505082410002ca214a9@mail.gmail.com> Reply-To: device-mapper development Mime-Version: 1.0 Content-Type: multipart/mixed; boundary="===============0714975048==" Return-path: In-Reply-To: <6262291505082410002ca214a9@mail.gmail.com> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: dm-devel-bounces@redhat.com Errors-To: dm-devel-bounces@redhat.com To: dm-devel@redhat.com List-Id: dm-devel.ids --===============0714975048== Content-Type: multipart/alternative; boundary="----=_Part_693_17149490.1124902881095" ------=_Part_693_17149490.1124902881095 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable Content-Disposition: inline ---------- Forwarded message ---------- From: Jacob Broido Date: Aug 24, 2005 7:00 PM Subject: Re: [dm-devel] cow snapshot on cloop device To: Kevin Corry I am using dmsetup directly. and I do the following: 1) Create an empty file that will be used as cow backing storage 2) losetup the backing file to /dev/loop0 3) create a snapshot of main root_device on /dev/loop0 4) mount the cow snapshot Here is the info you requested: The kernel is a - 2.6.11.10 + xen patch. =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D / # dmsetup ls root_master (253, 0) root_cow0 (253, 1) / # dmsetup table root_master: 0 4096128 linear 240:0 0=20 root_cow0: 0 4096128 snapshot 253:0 7:0 P 8 / # cat /proc/partitions major minor #blocks name 7 0 loop0 8 0 sda 8 1 sda1 8 2 sda2 8 3 sda3 240 0 cloop0 252 0 dm-0 253 1 dm-1 / # cat /proc/mounts rootfs / rootfs rw 0 0 /dev/root.old / ext2 rw 0 0 /proc /proc proc rw,noadirtime 0 0 /sys /sys sysfs rw 0 0 /dev/hdc /cdrom iso9660 ro 0 0 /ramdisk /ramdisk tmpfs rw 0 0 /dev/mapper/root_cow0 /cow ext2 rw.noatime 0 0 =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D On 8/24/05, Kevin Corry wrote:=20 >=20 > On Wed August 24 2005 11:35 am, Jacob Broido wrote: > > Hi, > > I am trying to set a cow snapshot on a cloop device.=20 > > I managed to create a snapshot and mount it as read/write, but it=20 > appears > > that the data inside the /cloop appears invalid: > > > > Binary executables appear to be invalid, I perfomed diff between files= =20 > on=20 > > snapshotted /dev/cloop, and the same files accessed directly through=20 > cloop. > > > > The files were diffrent, > > anyone has idea as to what can be the reason for this? >=20 > Are you using LVM, EVMS, or dmsetup to create your snapshot? Please send= =20 > in=20 > the output from "dmsetup ls" and "dmsetup table", as well as the contents > of /proc/partitions and /proc/mounts, after you have activated and mounte= d > your snapshot. >=20 > -- > Kevin Corry > kevcorry@us.ibm.com > http://www.ibm.com/linux/ > http://evms.sourceforge.net/ >=20 --=20 Not gonna be king of the world if you're slave to the grind - Skid Row=20 --=20 Not gonna be king of the world if you're slave to the grind - Skid Row ------=_Part_693_17149490.1124902881095 Content-Type: text/html; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable Content-Disposition: inline

---------- Forwarded message ----------
From: Jacob Broido <jacob.broido@gmail.com>
Date: Aug 24,= 2005 7:00 PM
Subject: Re: [dm-devel] cow snapshot on cloop device
To: Kevin Corry= <kevcorry@us.ibm.com>
=
I am using dmsetup directly. and I do the following:
1) Create an empty file that will be used as cow backing storage
2) losetup the backing file to /dev/loop0
3) create a snapshot of main root_device on /dev/loop0
4) mount the cow snapshot


Here is the info you requested:
The kernel is a - 2.6.11.10 + xen patch. =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D
/ # dmsetup ls
root_master         (253, 0)
root_cow0        (253, 1)
/ # dmsetup table
root_master: 0 4096128 linear 240:0 0
root_cow0: 0 4096128 snapshot 253:0 7:0 P 8

/ # cat /proc/partitions

major minor  #blocks    name

7    0        loop0
8    0        sda
8    1        sda1
8    2        sda2
8    3        sda3
240    0        cloop0
252    0        dm-0
253    1        dm-1

/ # cat /proc/mounts
rootfs / rootfs rw 0 0
/dev/root.old  / ext2 rw 0 0
/proc /proc proc rw,noadirtime 0 0
/sys  /sys sysfs rw 0 0
/dev/hdc /cdrom iso9660 ro 0 0
/ramdisk /ramdisk tmpfs rw 0 0
/dev/mapper/root_cow0 /cow ext2 rw.noatime 0 0
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D


On 8/24/05, Kevin Corr= y < kevcorry@us.ibm.com> wrote:
On Wed Aug= ust 24 2005 11:35 am, Jacob Broido wrote:
> Hi,
> I am trying t= o set a cow snapshot on a cloop device.
> I managed to create a snapshot and mount it as read/write, but it = appears
> that the data inside the /cloop appears invalid:
>> Binary executables appear to be invalid, I perfomed diff between file= s on
> snapshotted /dev/cloop, and the same files accessed directly throu= gh cloop.
>
> The files were diffrent,
> anyone has idea = as to what can be the reason for this?

Are you using LVM, EVMS, or d= msetup to create your snapshot? Please send in
the output from "dmsetup ls" and "dmsetup table", a= s well as the contents
of /proc/partitions and /proc/mounts, after you h= ave activated and mounted
your snapshot.

--
Kevin Corry
kevcorry@us.ibm.com
http://www.ibm.com/linux/
h= ttp://evms.sourceforge.net/



--
Not gonna be king of the world if you're slave = to the grind
- Skid Row


--
Not gonna be king of the world if= you're slave to the grind
- Skid Row ------=_Part_693_17149490.1124902881095-- --===============0714975048== Content-Type: text/plain; charset="us-ascii" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Content-Disposition: inline --===============0714975048==--