[sclug] RAID and/or LVM for ganging together HDDs to expand capacity?

[Tom Dawes-Gamble]

On Fri, 2007-10-19 at 01:18 +0100, John Stumbles wrote:
> Tom Dawes-Gamble wrote:
> 
> > Once you start running out of space again just buy another disk and add
> > that in to the Volume group in the same way.
> 
> I wouldn't want to permanently increase the number of disks I'm running. 
> Would there be a way of migrating the data from the smaller disk to a 
> new, bigger one and removing the small one?
> 

I believe you can.  But I've never tried it on Linux LVM.

I don't know of any way to convert your 300G drive to LVM on the fly so
to speak. In this first instance you have to add the 500Gig drive and
just copy as I outlined before.

Once you get to the point you need a bigger disk you buy say a 1Tb disk
and add it to the volume group.  Then pvmove the extents on the 500G
drive to the 1T drive then vgreduce the 500G drive out of the Volume
Group.  

You could test this by say not initially using the whole of the 500G
drive.  Leave say 100G free.  Add in the 300G drive and create an LV
that will fit in the 100G free space and then pvmove it to and from the
300G drive then when your done vgreduce the 300G drive out of the VG and
lvreduce the test partition and then lvextend the LV to use the entire
disk.

regards,
Tom.