OMS history cache hitrate 
OMS history cache hitrate <percentage>%, <number> of <number of> accesses failed
This
message can occur for
liveCache
instances only.
The
hit rate when accessing the
history data in
the
data
cache is too low. In a running liveCache application, the hit rate should
not fall below 100%, otherwise the data must be read physically.
The hit rate may fall for short periods of time, for example, when objects are accessed for the first time.
Check the following points:
data cache
OMS versions