FAST '24 - I/O in a Flash: Evolution of ONTAP to Low-Latency SSDs Matthew Curtis-Maury, Ram Kesavan, Bharadwaj V R, Nikhil Mattankot, Vania Fang, Yash Trivedi, Kesari Mishra, and Qin Li, NetApp, Inc Flash-based persistent storage media are capable of sub-millisecond latency I/O. However, a storage architecture optimized for spinning drives may contain software delays that make it impractical for use with such media. The NetApp® ONTAP® storage system was designed originally for spinning drives, and needed alterations before it was productized as an all-SSD system. In this paper, we focus on the changes made to the read I/O path over the last several years, which have been crucial to this transformation, and present them in chronological fashion together with the associated performance analysis. View the full FAST '24 program at https://www.usenix.org/conference/fast24/technical-sessions