Issues reported in Unisphere Diagnostic Report (LUN, Thin Pool )

(1) By it's nature, every Pool on VNX is "Thin", that is, Thin-Provisioned.  You can choose to "Thick" provision LUNs on a Thin Pool, i.e., tell the VNX to allocate 100% of the space requested and reserve it for your LUNs.  According to your statemen, this is what you've done.  The warning itself is meaningless in your case, as your LUNs will be able to use 100% of their allocated capacity, with no fear of pool exhaustion.

(2) Every VNX uses its first four drives (often referred to as the "System Drives" or the "Vault Area" for us old-timers) to hold the VNX Operating Environment.  Best practice recommends that you avoid putting high-I/O workloads on these drives, as it can adversely affect system performance.  Think of it like putting a high-transaction Oracle workload on the same disks that hold the operating system.

(3) How many drives do you actually have in your VNX5200?  Based on your statements, it makes me think you only have four drives in total.  If that's the case, there's not much you can do about it (short of adding more disks), so I'd ignore these warnings.  Basically, EMC is warning you that you run the risk of degraded performance during the upgrade (as the VNX will trespass LUNs between SPs for the upgrade). 

Fortunately, the OS upgrade will not delete your LUNs or affect any of the space you've provisioned, but those messages are undoubtedly unnerving.  As long as you have redundant paths to your ESX hosts, you should be just fine.

Let us know if that helps!

Karl