There is currently an issue with the vSphere 5.1 performance history charts. The symptoms are straight forward:
- You see only the last 30 days of performance history in the ‘past year’ view
- Only one month of performance history appears when trying to see the past year
VMware is working on a solution for the problem currently. It appears that the problem has been identified (stored procedure purging data) and hopefully a fix will be released soon.
Please subscribe to the following KB to be kept up to date: http://kb.vmware.com/kb/2042164