Thank you for this information, Paul.
Unfortunately, you don't have enough free disk space to perform the upgrade. You will have to add more storage capacity to your ESXi server hosting Admin VM in order to be able to upgrade. You have three options to do this:
1. Add more storage to the server and setup a separate array with 1.5 TB of available storage on the same server. Then you can deploy 2.5 on that array and migrate the data from 1.5.
2. Add a SAN datastore of 1.5 TB in size to this C-series server and dedicate it to 2.5 system.
3. Add more drives and rebuilding the existing array and RAID setup. This requires a rebuild of the entire 1.5 system and restore from backup (if you have NFS storage configured and backups running). If you have to do this as the only option, what you can do is put the system in MM, and gracefully power it off. Then copy Admin VM Hard Disk 4 (VMDK file that represents Hard Disk 4) off the server. After this was done, add more storage and rebuild the array. Then deploy 2.5 Admin and IRP VMs as you are doing a new deployment, but make sure they don't power on after deployment (there is an option to UNCHECK during manual OVA deployment of the VMs, so the VMs don't start after deployment). Finally, move the VMDK file to 2.5 Admin VM, and then power on the VMs. This is pretty much doing the Manual Upgrade and all the instructions about moving the VMDK file can be found in the documentation.
With Automatic Upgrade, you need to ensure many different things:
1. Dedicate a temporary IP address and host name for 2.5 Upgrade Admin VM
2. You cannot have Distributed vSwitch configured on your ESXi host as automatic upgrade cannot perform a successful deployment of the VMs in that case (you have to use Standard vSwitch)
3. You have to ensure that NTP client is started on ESXi hosts, that it is configured to Start and Stop with host, and that time is in sync. If the time is not in sync, you will have to put the system into Maintenance Mode, gracefully shut down the VMs (right-click the VM in vCenter > Power > Shut Down Guest) and then correct the time, ensure NTP is configured properly, and then power on the VMs)
4. You have to ensure that your vCenter is accessible using vCenter server hostname and not IP address as the upgrade wizard has to connect to vCenter using FQDN and not the IP address of vCenter
5. Your DMZ Firewall must have all the same rules configured for the temp IP address and hostname as it does for the original Admin VM hostname and IP. That way, the wizard will have all the needed access rights to the ESXi host in the DMZ to create 2.5 VM
As you can see, there is a lot of prerequisites to doing the Automatic Upgrade. Still, if you think you can have all those fulfilled with little effort, you can do the automatic upgrade. Instructions for both automatic and manual upgrade can be found here:
http://www.cisco.com/c/en/us/td/docs/collaboration/CWMS/2_5/Administration_Guide/Administration_Guide/Administration_Guide_chapter_01010.html
As for the IRP, if you are doing an Automatic Upgrade, the upgrade wizard will guide you and IRP server will be created automatically. If you are doing a manual upgrade, then you will have to deploy both Admin and IRP VMs separately (using the same 2.5 OVA file, just selecting a different VM option during the deployment), and before powering them on for the first time, you will have to copy the VMDK file (Hard Disk 4) from 1.5 Admin VM to 2.5 Admin VM as described in the instructions.
Please, let me know of any additional questions you might have.
-Dejan
