We currently have an old environment that needs to get upgraded, not just vmware but also hardware, and looking at best practice for this.
Vcenter running 5.5.0, 2183111 (enterprise plus license) inside Windows 2008 R2 (guest VM)
5 hosts in a cluster are running ESXi 5.5.0, 2302651 (Dell R710)
1 host outside the cluster but under same vcenter running ESXi 5.1.0, 1065491 (Dell R805)
The R805 has a couple of guests running on local drives. The rest all attached to an iSCSI SAN. We are replacing the hardware with 4x Dell R740 and at this point looking to upgrade to 6.5. Several guests are production so can't really have any down time. I do understand that the guests in the R805 would have to go down since they are not part of the cluster in order to move them into the cluster and SAN (or at least when I tried, that's what it said).
Was suggested at one point was to create a completely new Cluster and Vcenter on the new servers, and then migrate the guest VMs from one cluster to the other one. But not sure if this can be done while the guests are running. Networking is just vSwitches.
Otherwise, I know that the 5.1 host cannot go straight to 6.5. Since that has a couple of VMs only, we thought of moving them to another host and inside the cluster. Then we would decommission the old host, and start an upgrade from 5.5 to 6.5. We would upgrade Vcenter and then bring one of the new R740 into the cluster, move VMs to it, then continue bringing in the new hosts and decommissioning the old ones (don't have physical space to add all new hosts at once) and we may need to reuse IP addresses.
Any pointers as to which is better? TIA.
