Product : HPE, VSA [SDS]/12.7, x86
Feature : Flash Purpose, Flash, Storage Support
Content Owner:  Herman Rutten
Summary
Storage Tier (+ Write Cache)
Details
SSD is primarily meant as a high-performance storage tier. To make optimal use of the flash layer in hybrid configurations, the Adaptive Optimization (AO) feature can be enabled. AO is a simple and smart sub-volume auto-tiering feature that transparantly moves more frequently accessed blocks in 256KB segments to the Tier-0 flash storage tier and keeps the infrequently accessed blocks on Tier-1 with lower performance and potentially lower-cost hard disk
drive (HDD) storage.

When using AO, new writes will always arrive at the fastest tier (Tier 0 = SSD). The algorithm logic ensures there is always a small amount of free space reserved on the fastest tier to accomodate new writes..