Adaptive Flash Cache overview

HPE 3PAR Adaptive Flash Cache consists of features that extend the system cache on HPE 3PAR Storage systems that have a combination of SSD physical drives, hard disk physical drives, and SCM drives.

The features are installed on storage systems as part of certain versions of HPE Storage OS and do not require a license to use. For information about HPE 3PAR Storage platform support, see the HPE SSMC Administrator Guide.

Adaptive Flash Cache extends the storage system DRAM cache by using a portion of the SSD physical drive capacity to cache the read requests for the hard disk physical drives. The storage system handles read requests using the DRAM cache up to 90 percent of DRAM utilization, and then small blocks (less than 64 KiB) of random read data are automatically moved to the SSD extended cache.

  • Adaptive Flash Cache can also use SCM drive as a read cache extension for the All Flash storage systems. The main purpose of SCM module is to reduce read latency from the host application.

  • Reports can be generated for the capacity and performance of SCM drives.

  • Adaptive Flash Cache with the SCM modules uses NVMe (Non-Volatile Memory Express). NVMe is an industry standard specification and an interface for communication with a Non-Volatile Memory subsystem. NVMe SCM module is designed for high performance, concurrence and also for low-latency media. The Systems screen displays the NVMe SCM module utilization.

  • Adaptive Flash Cache can be enabled for all virtual volumes on a storage system or for only the virtual volumes that are in virtual volume sets.

  • A storage system must have at least 64 GiB of SSD space per controller node pair and must be configured in 16 GiB increments. The maximum SSD space in a configuration depends on the storage system model.

  • A built-in simulation mode can be used in conjunction with the System Reporter Adaptive Flash Cache - Performance Statistics report to see how Adaptive Flash Cache would perform on a storage system that does not currently include SSD physical drives.

  • When using SCM drives, Raid 0 is the only supported RAID option and Standard is the only supported Mode option. The maximum capacity for an SCM drive is the cache size. A user does not have the privilege to change or specify the cache size. You can filter the Physical Drives using the SCM device type filter.