High availability comes in many forms but a combination of clustering and virtualisation is always going to be interesting!
This customer has been using XEN in SLES for a while now and was looking for more redundancy. So when hardware renewal time came rolling around, we worked out that they could get three IBM x3550s for less than they had paid for their original x346!! Cluster time….
As they had been a SLES customer for a while and kept their maintenance going, they were automatically licensed for the HA Extension (it’s not exactly expensive anyway). We added a couple of decent sized QNAP NAS boxes with lots of disk in RAID 10 and set up iSCSI on dedicated switches. Next step, format the LUs with OCFS2, create the cluster resources for OCFS2 and we’re ready to go! The domUs were copied over from the old XEN hosts and tested locally. No problems there, so each XEN domU then became a cluster resource! The XEN daemons on the nodes and the resources were then configured for live migrate and the virtual machines can now migrate around the cluster without being shut down, yes, even the Windows ones as they have the Virtual Machine Driver Pack installed…