Re: [linux-lvm] lvcreate --snapshot ---> file descriptor 7 left open?

["Donald Murray, P.Eng." <donaldm314 gmail com>]

We currently use LVM2 snapshots to backup a MySQL database. To quiesce
our database we issue a 'flush tables with read lock', then snapshot,
then release
the lock. 

This approach yields consistent snapshots of our database. 

We do our snapshot in a Perl script. This allows us to create and hold
a connection to the database during the entire flush, snapshot, unlock
process. I don't think you'll be able to do that directly in ksh. The 'flush
tables with read lock' only persists as long as the connection is active.


On 8/17/05, Lutz Reinegger t-systems com <Lutz Reinegger t-systems com> wrote:
> Hey there,
> 
> currently I am testing a small backup script (ksh) which is supposed to create snapshots
> of my MySQL database file systems using the Linux LVM2 snapshot feature.
> 
> Here is the command I am using:
> "/usr/sbin/lvcreate -L 10240M --snapshot -p r -n mysqlsnap /dev/datavg/mysqllv"
> 
> It works fine so far ($? = 0), however I am seeing some kind of strange messages:
> "
> File descriptor 7 left open
>   Logical volume "mysqlsnap" created
> "
> 
> A month ago Jürgen reported similar messages using "lvdisplay":
> https://www.redhat.com/archives/linux-lvm/2005-July/msg00069.html
> Alasdair then pointed out that this message is (only?) a warning message:
> https://www.redhat.com/archives/linux-lvm/2005-July/msg00070.html
> 
> Here 's my question:
> Do I have to be worried about the consistency of my snapshots in any way
> because of this message?
> 
> Operating system  : RedHat Enterprise Linux 4 for IA32 + latest patches.
> Kernel version    : 2.6.9-11.ELsmp
> 
> lvm> version
>   LVM version     : 2.01.08 (2005-03-22)
>   Library version : 1.01.01 (2005-03-29)
>   Driver version  : 4.4.0
> lvm>
> 
> Kind regards
> Lutz Reinegger
> 
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