IT organizations and DBA teams typically deal with tradeoffs between IOPS and latency. For example, the greater the number of databases, the more IOPS on the storage array and the greater the latency. This tradeoff between IOPS and latency happens over time. Initially, storage performance is good, and databases have low latency times. With time, more applications are added to the array and the tradeoff is weighted toward IOPS, thus adversely impacting database and application performance.

In testing this architecture with mixed databases and workloads, we consolidated eight databases (five SQL Server databases and three Oracle databases) to determine where the tradeoff between IOPS and latency occurred on the PowerMax 2000 array. With eight databases running in parallel, we generated a total of 106,139 IOPS for 24 NVMe flash drives. The following table combines the IOPS, latencies, and throughput test results for all mixed workloads in the validation tests:  

Table 19.        IOPS, average read latencies, and throughput across all workloads

With all the workloads running in parallel, the PowerMax array supported over 105,000 IOPS and maintained average read latencies under 1 ms for all databases except the snapshot OLTP SQL Server 1 database. We allocated minimum memory to the databases to force more physical reads from storage. For example, we allocated only 8 GB to the SQL Server databases. Most customers will provide more memory to their databases, so their average read latencies will be shorter.

Average write latencies across all workload use cases were consistently low with most under .31 ms. The only exception is the average write latency for the OLTP Oracle database which is .75 ms for the log LUN. All average write latencies were well under the goal of 1 ms or less for storage performance, as shown in the following table:

Table 20.        IOPS, average write latencies, and throughput across all workloads

Our findings show that there was no tradeoff between IOPS and storage latencies despite the entry-level PowerMax 2000 configuration with 24 NVMe flash drives having to support eight databases and a mixture of OLTP and DSS workloads. Customers can be confident that a properly sized mixed database/mixed workload solution based on PowerEdge MX840c servers and PowerMax 2000 arrays can scale while providing strong storage performance.