On single-tier-based PowerMax all-flash systems, PowerMaxOS service levels enable performance management of all the data for each SG without having to move any of the data. The latest PowerMaxOS release includes support for a tiered storage model called automated data placement (ADP). ADP is enabled by the PowerMaxOS service levels and augmented by machine learning to place the most active data on faster storage drive technology.
PowerMaxOS uses real-time machine learning to model workload characteristics. This model provides a predictive function that enables PowerMaxOS to anticipate workload demand for a storage group. With these anticipated workload demands, PowerMax OS can adapt as necessary to changes in block size, write ratio, or I/O load. ADP movements occur as either promotion of active data to SCM or demotion from an SCM storage tier. The service levels are defined with target response time characteristics. Service levels also have either an upper response time limit or both upper and lower response time limits to avoid the over-allocation of shared resources for low-priority applications.
A storage group with a higher-priority service level that is affected by any lower-priority storage groups triggers response-time management to the lower-priority service levels. When the higher-priority storage group reaches its target response time, all lower storage groups continue to be managed until the lowest-priority storage groups reach their target response time. The management of any lower-priority service level is imposed by a response-time delay in I/O. The delay gradually increases over time to keep the higher-priority storage group within its respective target response time. The delay gradually decreases to ensure that the higher-priority storage group remains within its response time.
PowerMaxOS offers the following service levels and associated response times. It also sets service-level bias to apply promotion and demotion priorities.
The following figure illustrates PowerMaxOS service levels:
Figure 6. PowerMaxOS service levels