Easy Tier function
The system includes IBM® Easy Tier®, which is a function that responds to the presence of drives in a storage pool that also contains hard disk drives (HDDs). The system automatically and nondisruptively moves frequently accessed data from HDD MDisks to flash-based storage MDisks, thus placing such data in a faster tier of storage.
Easy Tier eliminates manual intervention when you assign highly active data on volumes to faster responding storage. In this dynamically tiered environment, data movement is seamless to the host application regardless of the storage tier in which the data belongs. However, you can manually change the default behavior. For example, you can turn off Easy Tier on pools that have any combination of the four types of MDisks.
All MDisks belong to one of the tiers, which includes MDisks that are not yet part of a pool.
If a pool contains one type of MDisk, Easy Tier goes into
balancing
mode. When the pool
contains multiple types of MDisks, Easy Tier is automatically
turned on. The local MDisks are classified as
storage class memory, tier 0 flash, tier 1 flash, enterprise, or nearline drives. The system
supports storage class memory, tier 0, and tier 1 flash drives. Storage class memory drives use
Non-Volatile Memory Express (NVMe) technology that provides faster performance than the traditional
SSDs but are slower than dynamic random-access memory (DRAM)-based drives. Tier 0 flash drives are
higher-cost flash drives that provide high performance for read and write operations. Tier 1 flash
drives are lower-cost flash drives that have large capacity but lower performance and write
endurance characteristics.