About cookies on this site Our websites require some cookies to function properly (required). In addition, other cookies may be used with your consent to analyze site usage, improve the user experience and for advertising. For more information, please review your options. By visiting our website, you agree to our processing of information as described in IBM’sprivacy statement. To provide a smooth navigation, your cookie preferences will be shared across the IBM web domains listed here.
Publication
SYSTOR 2024
Conference paper
Exploring I/O Management Performance in ZNS with ConfZNS++
Abstract
Flash-based storage is known to suffer from performance unpredictability due to interference between host-issued I/O and device-side I/O management. SSDs with data placement capabilities, such as Zoned Namespaces (ZNS) and Flexible Data Placement (FDP), expose selective device-side I/O management operations to the host to provide predictable performance. In this paper, we demonstrate that these host-issued I/O management operations lead to performance interference with host-issued I/O. Indeed, we find that the I/O management operations introduced by ZNS and FDP create I/O interference, leading to significant performance losses. Despite the performance implications, we observe that ZNS research frequently uses emulators (over 20 recently published papers), but no emulator currently has function-realistic models for I/O management. To address this gap, we identify ten ZNS I/O management designs, explain how they interfere with I/O, and introduce ConfZNS++, a function-realistic emulator with native I/O management support, providing future research with the capability to explore these designs. Additionally, we introduce two actionable host-managed solutions to reduce ZNS management interference: ZINC, an I/O scheduler prioritizing I/O over I/O management, and the softfinish operation, a host-managed implementation of the finish operation. In our experiments, ZINC reduces reset interference by 56.9%, and softfinish reduces finish interference by 50.7%.