On Fri, 2010-11-19 at 11:24 +0000, Ashley Large wrote: > My thoughts have been to have 3 âfront endâ physical host machines > with a rough 50/50 split of the current 25 odd servers into VMs on > these physical hosts. I will then have redundancy across 3 machines so > that if machine 1 dies, the vms are moved to machine 2 or 3 pending > fix of machine 1. Then I want to create two âback endâ storage servers > which are replicated and provide redundant storage to the front ends > in a primary/secondary way such that the front ends can failover to > either available storage server. I am anticipating having only VM host > booting off machine1-3 and using the back end storage servers for > booting the vms and storing their data. Each storage server will have > 6 x 2Tb sata disks set up as a 6Tb raid1 array although I have been > reading that more spindles is better so maybe I need more disks for > optimal performance. Front ends and back ends would have multiple > bonded Gig e ports to a dedicated switch which I think should provide > enough bandwidth and the net facing NICs running off a separate > switch. I've built a very similar system on top of Centos 5 / RHCS. I used drbd on top of LVM to replicate the data across the two storage machines, and then iscsi to export the storage to the VM nodes. I used xen for virtualization. While my system seemed to be pretty much ok, I experienced random crashes on virtual machines that (unfortunately) were windows. The crash however resided not in the virtual machine itself, but in the virtualization system (segfault in qemu-dm). The crashes seem to be related to moving storage resources across the two nodes, but however they cannot be 100% replicated. I also experienced file corruption inside the VMs. I'm pretty sure that under certain circumstances some block writes are lost, but for now I didn't manage to figure out exactly where. Best regards, Radu Rendec -- Linux-cluster mailing list Linux-cluster@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/linux-cluster
