Multi-Tenant I/O Isolation with Open-Channel SSDs

Multi-tenancy environments rely at their core on fair resource distribution by the host system. For storage, this translates into the host managing throughput and latency needs for each tenant. In Solid State Drives (SSDs), throughput expectations are mostly met thanks to more powerful controllers and faster media. Latency guarantees, on the other hand, remain a challenge due to the unpredictability intrinsic to the design of current SSDs and the narrow interfaces available to the host. We propose the use of Open-Channel SSDs to partition the device into its physical units, accessible in parallel by the host, and mapped onto tenants via traditional block devices in order to provide I/O isolation. We describe our architecture and provide an experimental evaluation to show the benefits.