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From: "Donald Murray, P.Eng." <donaldm314@gmail.com>
To: LVM general discussion and development <linux-lvm@redhat.com>
Subject: Re: [linux-lvm] lvcreate --snapshot ---> file descriptor 7 left open?
Date: Wed, 17 Aug 2005 10:56:29 -0600	[thread overview]
Message-ID: <12984bb00508170956627f12f6@mail.gmail.com> (raw)
In-Reply-To: <DF6FD933C3914D409E8CA14EE01A026C02F14AA8@e8sbh.ditscom.dsh.de>

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 J�rgen 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
> 
> _______________________________________________
> linux-lvm mailing list
> linux-lvm@redhat.com
> https://www.redhat.com/mailman/listinfo/linux-lvm
> read the LVM HOW-TO at http://tldp.org/HOWTO/LVM-HOWTO/
>

      reply	other threads:[~2005-08-17 16:56 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2005-08-17 12:32 [linux-lvm] lvcreate --snapshot ---> file descriptor 7 left open? Lutz.Reinegger
2005-08-17 16:56 ` Donald Murray, P.Eng. [this message]

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