[linux-lvm] lvm on a single big partition or just a single big partition?

[Zhengquan Zhang]

On Wed, Jun 03, 2009 at 02:42:29PM -0400, Stuart D. Gathman wrote:
> On Wed, 3 Jun 2009, Zhengquan Zhang wrote:
> 
> > For one harddrive I often create a /boot parition that is not lvm and
> > create a huge partition on the rest of the harddrive for PV of lvm. Now
> > I am thinking what is the difference between doing partition like this
> > and just a single big partition without lvm?
> 
> With LVM, you can create many logical volumes.  If you only ever create one
> logical volume that fills the entire PV, and you aren't spanning drives
> (multiple PVs) or mirroring, then LVM is not doing anything for you.

That is what I am doing, so I am not fully utilizing lvm. another
question, is it advisable to create on pv for one harddrive? 

> 
> Even with just one LV, leave some space for a snapshot.  Then you can
> take more consistent backups by creating a snapshot of your main LV
> and backing that up instead.  Put your swap space in LVM as well.

Thanks for pointing out this. I never thought of leaving space for
snapshot. and the swap too, why it is good to put swap in lvm?

> 
> One reason to create multiple LVs is for virtual machines.  If you
> run Xen, VMWare, or other virtual machine, then each virtual machine
> should have its own LVs for disk drives.  This is more efficient
> than using a filesystem file for a virtual disk.

Oh really, I never thought about this, so virtual machine can directly
use lv for the as their filesystem?

> 
> PS.  I wonder if Grub will ever support LVM?  Does LILO work with LVM?

As I know, LILO does, buy anyway we've got separate /boot.

Thanks a lot Stuart, it helped me a lot,

-- 
Zhengquan