The PowerStore base enclosure can be configured with NVMe SSDs or NVMe storage class memory (SCM) drives for user data. While NVMe SCM drives provide better performance, the disk capacity of an NVMe SCM-based appliance is limited to the disks in a base enclosure and cannot be expanded with an expansion enclosure. It is recommended that all drives within a PowerStore system be the same size to maximize the usable capacity from each drive. PowerStore systems require between six and 23 NVMe SSD drives in the base enclosure.
PowerStore uses NVMe NVRAM drives to provide persistent storage for cached write data. PowerStore 1000 and 3000 appliance models have two NVRAM drives per system, while the PowerStore 5000, 7000, and 9000 models have four NVRAM drives per system.
The following figure shows how the NVRAM drives are configured in the base enclosure.
NVMe SSD-based systems can also be expanded with an expansion enclosure using up to 25 SAS SSD drives to increase the amount of available storage capacity, as shown in the following figure:
The PowerStore Dynamic Resiliency Engine (DRE) is used to manage the drives in the system. RAID settings are not user-configurable within the PowerStore system. RAID 5 is used to protect user data that is stored on the drives based on the number of drives:
The system does not change the stripe width as more drives are added. Because
RAID 5 8+1 provides greater usable capacity from the same number of drives, we recommend initially installing a PowerStore system with a minimum of 10 drives.
All drives in the system are automatically used to provide storage capacity. User configuration of the drives is not necessary and dedicated hot spare drives are not required. Spare space for a rebuild is automatically distributed across all drives, providing better resource utilization and enabling a faster rebuild if there is a drive failure.