NetApp® E-Series storage arrays are often deployed in cluster environments that require high-bandwidth and low-latency performance. However, volume ownership thrashing and other multipath/failover issues have been longstanding challenges in clustered environments, especially when hosts running different OSs access the same storage volumes on the array.
Over the past two years, NetApp has released enhancements in the E-Series firmware that improve interoperability between hosts and E-Series arrays in heterogeneous host OS clustered environments. These changes have culminated in a new failover mode that greatly improves cluster interoperability, and these most recent enhancements are the next step in an ongoing evolution. This includes two new enhancements released in April 2017 that are designed to specifically resist cluster volume ownership thrash.
Options have existed in the past that allow multipath failover to be avoided in deployments where that option made sense, but now these new options exist to build cluster solutions without risk of ownership thrash while still retaining failover and host I/O access redundancy. For some limited configurations, options also exist to provide limited failback in clustered environments. This enables automatic recovery software to move LUN ownership back to preferred paths following the correction of SAN connectivity faults, again without the risk of LUN ownership thrash.
This paper includes an example of an E-Series array deployed using a thrash-resistant, redundant cluster and includes performance test results using a media application from Autodesk to generate the I/O and measure performance. The Autodesk self-certification test suites and stress tests were run on a StorNext cluster and a 96-drive E-Series E5624 storage system. Such workloads mimic the Autodesk Flame application, where the tests simulated multiple workstations playing back media with different frame sizes (HD, 2K, 4K) and combinations of read and write operations simultaneously. The Autodesk self- certification test results and the Flame stress test suites results are covered in this report.