Described are techniques for selective data replication. Cached data is
replicated if it is characterized as critical. Critical data may include
data associated with a write I/O operation. Cache locations are selected
for replicated data so that a first location is mapped to a first memory
board and a second location is mapped to a second memory board. Data for
a read operation is not replicated in cache. Other non-cache data that is
critical and thus replicated includes metadata. Cache locations for data
of read and write I/O operations are selected dynamically at the time the
I/O operation is made from the same pool of cache locations.