After updating vCenter to 8.0U3b or later, some performance metrics (e.g. CPU > Ready) in 'Last year' chart shows higher values than before.
vSphere vCenter Server 8.0.3.00200 and newer
In versions of vCenter Server less than 8.0U3b (8.0.3.00200), there was an error in the calculation logic when rolling up from 'Last month' to 'Last year'.
For example, although the rollup type for CPU > Ready is summation, when rolled up to 'Last year', it was calculated as average in previous vCenter Server versions.
The calculation logic was fixed in vCenter 8.0U3b or later.
The calculated values before updating to vCenter 8.0U3b are incorrect, and the values after the update are correct.