FastFCoE : An Efficient and Scale-up Multi-core Framework for FCoE-based SAN Storage Systems

Due to the high complexity in software hierarchy and the shared queue & lock mechanism for synchronized access, existing I/O stack for remote target access in FCoE-based SAN storage becomes a performance bottleneck, thus leading to a high I/O overhead and limited I/O scalability in multi-core servers. For scalable performance, existing works focus on improving the efficiency of lock algorithm or reducing the number of synchronization points to decrease the synchronization overhead. However, the synchronization problem still exists and leads to a limited I/O scalability. In this paper, we propose FastFCoE, a protocol stack framework for remote storage access in FCoE based SAN storage. FastFCoE uses private per-CPU structures and disables the kernel preemption to process I/Os. This method avoids the synchronization overhead. For further I/O efficiency, FastFCoE directly maps the requests from the block-layer to the FCoE frames. A salient feature of FastFCoE is using the standard interfaces, thus supporting all upper softwares (such as existing file systems and applications) and offering flexible use in existing infrastructure (e.g., adaptors, switches, storage devices). Our results demonstrate that FastFCoE achieves efficient and scalable I/O throughput, obtaining 1107.3K/831.3K IOPS (5.43/4.88 times as much as Open-FCoE stack) for read/write requests.