For the second use case, we configured PMem in Memory (nonpersistent) Mode where it is available as additional system memory. This configuration enables us to access additional memory at the operating system level to provide an effective alternative to traditional DRAM in SQL Server. This memory is an extension of the memory available for the SQL Server buffer pool and data cache, or extended portions for in-memory environments.
The following figure shows the storage layout of the Optane server:
The larger amount of memory available for the operating system offers two options for:
To assess the capabilities of PMem in these test cases, we used a 3 TB database generated by using HammerDB with columnstore indexes. For details about the configuration, see Benchmarking configuration.
With an increased amount of available memory, the system with PMem used a larger buffer pool and data cache performance increased, especially during the throughput run.