Database performance issue

Hi,
We has site outage for a minute, probably due to DB issues. Statspack(1 hourly)  report of my 10.2.0.3 2 node RAC DB is as below.

Cache Sizes                       Begin        End
~~~~~~~~~~~                  ---------- ----------
               Buffer Cache:     8,992M             Std Block Size:         8K
           Shared Pool Size:    12,288M                 Log Buffer:    13,886K


Load Profile                            Per Second       Per Transaction
~~~~~~~~~~~~                       ---------------       ---------------
                  Redo size:            168,612.43                372.34
              Logical reads:             40,156.05                 88.68
              Block changes:              1,244.77                  2.75
             Physical reads:                120.77                      0.27
            Physical writes:                131.49                  0.29
                 User calls:              6,567.32                 14.50
                     Parses:              1,677.83                  3.71
                Hard parses:                  1.69                  0.00
                      Sorts:                294.47                  0.65
                     Logons:                  3.03                  0.01
                   Executes:              1,748.70                  3.86
               Transactions:                452.84

  % Blocks changed per Read:    3.10    Recursive Call %:    15.38
 Rollback per transaction %:   89.27       Rows per Sort:    64.72

Instance Efficiency Percentages
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
            Buffer Nowait %:  100.00       Redo NoWait %:  100.00
            Buffer  Hit   %:   99.75    In-memory Sort %:  100.00
            Library Hit   %:   99.91        Soft Parse %:   99.90
         Execute to Parse %:    4.05         Latch Hit %:   99.95