Some Performance Data Is Not Displayed After VirtualCenter Upgrade (5211358)
After you upgrade from VirtualCenter 1.x to VirtualCenter 2.x, the performance statistics data for the past few days might be missing. The statistics are lost because they were cached in local memory on the VirtualCenter system, and had not been written to the database at the time of the upgrade.
The lost statistics data cannot be recovered. However, the data loss is a one-time problem that occurs only at the time of an upgrade from VirtualCenter 1.x to VirtualCenter 2.x. Additional losses of performance statistics will not occur.