[linux-lvm] Volume Group Size

Ragnar Kjørstad lvm at ragnark.vestdata.no
Wed Jun 25 13:12:02 UTC 2003

On Wed, Jun 25, 2003 at 11:46:34AM -0600, Andreas Dilger wrote:
> On Jun 25, 2003  18:00 +0100, Stuart Fox wrote:
> > I cant find information about the maximum volume group size in the current
> > 2.4  series kernel.
> > 
> > Id like to be able to join 2 1.75Tb raid arrays into  1 3.5Tb array.
> > Is this possible?
> No, there is a limit of 2TB for all block devices in 2.4 kernels.  With
> 2.5, there is a "large block device" configure option that lets you have
> larger block devices.  There is apparently also a patch to support this
> on 2.4 kernels, but AFAIK it is not very widely used/tested.

The question was regarding volum goups, not logical volums.

So, correct me if I'm wrong, but I think the answer is yes, you will be 
able to join 2 1.75 Tb volume groups into a single 3.5 Tb volum group, 
if only an apropriate extent-size was set on VG-creation.

However, each Logical Volum in the Volum-Group need to be smaller than 2

AFAIK the "large block device" feature in 2.5 does not enable > 2TB
logical volumes - it only fixes the general block-device layer, md and
the scsi-subsystem. At least that used to be the case - maybe someone
knows if it has changed?

Ragnar Kjørstad

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