[linux-lvm] LVM2 snapshot contents on a reboot

[linux-lvm] LVM2 snapshot contents on a reboot

[Vasan V S]

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Hi all,

We are using the latest version of LVM2 and creating a snapshot LV (This is
a fresh snapshot LV and we are not attempting to migrate from LVM1).
However, on rebooting the server, we find the snapshot contents are getting
synced up with the original source volume contents completely. Any changes
that has been made in the source volume after the snapshot volume has been
taken is getting reflected in the snapshot volume as well after the reboot.

The following are the commands that we are using:

For the creation of snapshot:

lvcreate -s -L <snap size> -n <snapshot Name> -p <R-W permission> <original
volume>

For deleting the snapshot:

lvremove -f <snap shot node entry>

However, if the server (running Linux 2.6.15.4) is not rebooted, the
snapshot contents are correctly shown even if there has been any changes on
the source volume.

Should we do anything specific at the time of the server shutdown to ensure
that the snapshot contents should not be getting synced with the source
volume on start up?

Please advice.

Thanks

vasan

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Re: [linux-lvm] LVM2 snapshot contents on a reboot

[Peter Rockai]

On Wed, Nov 22, 2006 at 07:51:33PM +0530, Vasan V S wrote:
[snip]
> For the creation of snapshot:
> 
> lvcreate -s -L <snap size> -n <snapshot Name> -p <R-W permission> <original
> volume>
> 
> For deleting the snapshot:
> 
> lvremove -f <snap shot node entry>
Why/when are you removing the snapshot?

> However, if the server (running Linux 2.6.15.4) is not rebooted, the
> snapshot contents are correctly shown even if there has been any changes on
> the source volume.
As expected.

> Should we do anything specific at the time of the server shutdown to ensure
> that the snapshot contents should not be getting synced with the source
> volume on start up?
No, you just create the snapshot once and leave it be, it'll stay
around until you lvremove it.

Yours, Peter.

-- 
Peter Rockai | me()mornfall!net | prockai()redhat!com
 http://blog.mornfall.net | http://web.mornfall.net

"In My Egotistical Opinion, most people's C programs should be
 indented six feet downward and covered with dirt."
     -- Blair P. Houghton on the subject of C program indentation

[linux-lvm] LVM2 snapshot contents on a reboot

[Vasan]

Hi all,

We are using the latest version of LVM2 and creating a snapshot LV
(This is a fresh snapshot LV and we are not attempting to migrate from
LVM1). However, on rebooting the server, we find the snapshot contents
are getting synced up with the original source volume contents
completely. Any changes that has been made in the source volume after
the snapshot volume has been taken is getting reflected in the
snapshot volume as well after the reboot.

The following are the commands that we are using:

For the creation of snapshot:

lvcreate -s -L  <snap size> -n <snapshot Name> -p <R-W permission>
<original volume>

 However, if the server (running Linux  2.6.15.4) is not rebooted, the
snapshot contents are correctly shown even if there has been any
changes on the source volume.

Should we do anything specific at the time of the server shutdown to
ensure that the snapshot contents should not be getting synced with
the source volume on start up?

The following are the versions that we are using from a LVM perspective:

-bash-3.00# lvs --version
LVM version:     2.02.13 (2006-10-27)
Library version: 1.02.10 (2006-09-19)
Driver version:  4.4.0

Please advice.

Thanks

Srini