[linux-lvm] Enterprise Backup Software with good support for LVM

[linux-lvm] Enterprise Backup Software with good support for LVM

[Mark F]

Could someone suggest an Enterprise Backup package that has good support 
for LVM (LVM2 in this case) on Linux (Specifically Suse Linux Enterprise 
9) Most products I've seen say they support block level backups but 
don't specifically say they support LVM.

Thanks,
-Mark

Re: [linux-lvm] Enterprise Backup Software with good support for LVM

[Michael Loftis]

--On November 29, 2005 12:03:39 PM -0600 Mark F <mfaine@knology.net> wrote:

> Could someone suggest an Enterprise Backup package that has good support
> for LVM (LVM2 in this case) on Linux (Specifically Suse Linux Enterprise
> 9) Most products I've seen say they support block level backups but don't
> specifically say they support LVM.

LVM provides a block level device.  However you don't want to back up there 
anyway, you'll just end up with corrupt garbage.  You need to back up at 
the filesystem level unless you're using your LVM LVs for Oracle or 
something similar in which case the backup software needs to support that 
by putting Oracle or the related application into the correct hot backup 
mode before attempting to directly read the LVM data, as well as backing up 
the transaction/redo logs.

[linux-lvm] Re: Enterprise Backup Software with good support for LVM

[Mark F]

Michael Loftis wrote:
> 
> 
> --On November 29, 2005 12:03:39 PM -0600 Mark F <mfaine@knology.net> wrote:
> 
>> Could someone suggest an Enterprise Backup package that has good support
>> for LVM (LVM2 in this case) on Linux (Specifically Suse Linux Enterprise
>> 9) Most products I've seen say they support block level backups but don't
>> specifically say they support LVM.
> 
> 
> LVM provides a block level device.  However you don't want to back up 
> there anyway, you'll just end up with corrupt garbage.  You need to back 
> up at the filesystem level unless you're using your LVM LVs for Oracle 
> or something similar in which case the backup software needs to support 
> that by putting Oracle or the related application into the correct hot 
> backup mode before attempting to directly read the LVM data, as well as 
> backing up the transaction/redo logs.
> 
> 
> _______________________________________________
> 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/
> 
Our data center is using Veritas Netbackup (currently 4.5 but soon to be 
5.1).  We are preparing some new servers for production and would like 
to use LVM2 but I'm not sure if this will present a problem for the 
Veritas Netbackup agent. I don't know if the backup agent software will 
support it or if it will even know the difference.

Is anyone using it?  Or does anyone have any reason to believe it 
will/won't work?

Thanks,
-Mark

Re: [linux-lvm] Re: Enterprise Backup Software with good support for LVM

[Graham Wood]

On Tue, Nov 29, 2005 at 12:40:02PM -0600, Mark F wrote:
> Michael Loftis wrote:
> Is anyone using it?  Or does anyone have any reason to believe it 
> will/won't work?
Netbackup does a file level backup, rather than block level.  This means 
that the filesystem used is not relevant, and the underlying structure
even more so.

E.g. it works at the directory/file level - so it backs up the files
that it finds and doesn't care what sort of block device is under that.

(That's assuming you're doing file backups, and not raw devices for DBs)

Re: [linux-lvm] Enterprise Backup Software with good support for LVM

[Graham Wood]

On Tue, Nov 29, 2005 at 11:29:19AM -0700, Michael Loftis wrote:
> LVM provides a block level device.  However you don't want to back up there 
> anyway, you'll just end up with corrupt garbage.  You need to back up at 
> the filesystem level unless you're using your LVM LVs for Oracle or 
> something similar in which case the backup software needs to support that 
> by putting Oracle or the related application into the correct hot backup 
> mode before attempting to directly read the LVM data, as well as backing up 
> the transaction/redo logs.

Surely by using snapshots, a block level backup could be "OK".  You'd
need to (ideally) tell the file-system layer to put the machine into a
fit state to be snapshotted (quick & dirty, obviously issues with it,
you could remount it readonly, snapshot, and then mount read-write
again).  It's also going to backup dead space, which is going to waste
backup media (e.g. tape) at best, and leak information at worst.

If you have a journalling filesystem, then taking a snapshot of the
active device would probably be acceptable...  Not ideal, but depending
on the relative importance of getting a perfect backup/restore and
reducing the load on the system while the backup is being done, it might
be acceptable to most people.

Obviously if your backup solution can tie into the filesystem's own
backup utilities then you're going to get a better result, but for some
people that's not the important thing (and not an option in backup
utilities for others).

I know that dump/restore on solaris is unsafe to use on live partitions,
I can't see any reference within the dump man pages to see if the same
applies to linux, and have never used it in anger on an active
filesystem - old habits die hard, so I do my best to keep it inactive
when using it.

Graham