High Availability Cluster with Combining NAS and ISCSI
To meet enterprise and grand challenge-scale performance and high availability requirements, a new type of storage cluster - iSCSI-based NAS cluster (iNC) is being designed. There are many advantages in an iNC system: firstly, it provides scalability without the added complexity by a single consolidated centralized storage management view for integrating multi-NAS with multi-user virtualized file system; secondly, it provides the flexibility for application by combining file-based NAS and block-based SANs via iSCSI in the same device; thirdly, it provides high performance and high availability by load-balancing and fault-tolerating mechanism; finally, it eliminates the single failure point and the bottleneck of I/O performance for the metadata server by storage agency. In this paper, we describe an implementation that demonstrates and validates iNC' potential. The I/O throughput for both file and block I/O requests, and the availability of our prototype are higher than that of NAS