Product : Dell EMC, PowerFlex [SDS]/3.5, Enterprise
Feature : Memory Purpose, Memory, Storage Support
Content Owner:  Herman Rutten
Read Cache
PowerFlex calls the use of DRAM as caching layer Read RAM Cache (rmcache). This is a tunable feature: rmcache can be enabled or disabled per volume.

Writes are only buffered in the host memory for Read after Write caching. One way to achieve Write buffering is to use Raid controllers (e.g. LSI, PMC etc.) that have battery backup for write buffering.