Re: [Xen-users] Re: Partition vs disk images

["Rob Greene" <robgreene@xxxxxxxxx>]

On Tue, Apr 29, 2008 at 10:15 PM, Fajar A. Nugraha <fajar@xxxxxxxxx> wrote:

In RHEL 5 at least, anaconda requires the block device/file to be mapped as disk (e.g hda, sda) not partition (e.g. sda1). Try changing it to
disk = [ "phy:lvm-raid/FileVolGroup,sda,w" ]

Ok, so (at least in CentOS/RHEL?) the Xen domU sees the dom0 partition not as a partition but as a physical disk?  sda1, sda, and hda all failed (sda1, sda were not visible while hda kept generating installer errors detecting the drives).  hda1 shows up as weirdly named disk  (/dev/hda1) that I need to partition out in the domU installer (ie, /dev/hda11, /dev/hda12, etc).

disk = [ "phy:lvm-raid/FileVolGroup,hda1,w",
         "phy:lvm-raid/io-swap,hda2,w" ]     # assumption was that these were partitions...

What concerns me is that if/when I want to grow disk available to a domU (this on in particular is a file server), I can't just grow what shows up as hda1, right?  I'd need to add a new "disk" and extend a LVM within the domU?

Don't these layers of RAID+LVM (dom0) and Xen block device and LVM (domU) come at a price?  I was hoping that the partition got mapped straight into the domU so I avoided any extra stuff within the domU and I would have the added bonus of being able to mount the drives and copy files between when setting this up.
 

Having said that, if you're building lots of identical domUs, using prebuilt template (and mappingthe block device  as sda1 instead of sda) should be faster than installer.

If I can only do partitions, how does this work then?  Unless all the drives are identical in size and I 'dd' the device??

Thanks!
-Rob
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