I lunged into Xen yesterday evening (and early this morning, it turned out). I built Xen 3.0.2 from source mostly following instructions from Xen Debian Quick Start. I used my existing Debian sarge install for Domain 0. I made a Debian sarge root image and swap following Creating a Debian VM with debootstrap. Then I cloned it and edited the hostname so I had two of them. Then, I configured the MAC address of their virtual adapters so I could set up static DHCP mappings and DNS entries on my LAN for them.
I wanted shared disk between my dom0 host and domX domains. NFS was, apparently, too easy for me, so I did some research into clustered filesystems to play with. I found two free possibilities that both looked reasonably mature and easy enough to install. GFS is from RedHat and OCFS2 is from Oracle. Both are open source. OCFS2 shipped with the kernel I already had built. GFS didn’t. So I decided to try OCFS2. I installed ocfs2-tools from Debian sarge. ocfs2_notes was a handy reference except I used ocfs2-tools from Debian sarge and the ocfs2 kernel module I built with the 2.6.16-xen kernel rather than installing from source as that guide shows. I set up a cluster named “ocfs2” with my two Xen domains and the host in it.
It seemed to work when running against a loopback file. I then brought the machine into single user and used parted to resize one of the partitions to make some free space to use LVM2 against. I created a logical volume to put the OCFS2 partition that will be shared between the Domain0 host and some of the DomainUs.
My plan is to set up some domains to continue to test Xen over a longer period of time. Assuming it all goes well I’ll eventually migrate the services from the other machine(s) they currently run on into domains.