VDM Godbole, C: Performance Evaluation of iSCSI Protocol for Mir

FC SAN has been the work-horse of the storage industry for quiet sometime now & has been the default transport protocol for data mirroring for disaster management and data recovery due to its performance advantages. But now with the increase in demand for mirroring solutions for small & medium sized businesses, the high acquisition and maintenance costs of FC have propelled iSCSI to be a cost-effective and viable alternative to FC. In this book, we attempt to evaluate the performance of mirroring over iSCSI and show that it can be performed satisfactorily and economically, without requiring the costlier FC option. This study involves the use of a customized caching algorithm deployed on a SAN for a remote mirroring application running on iSCSI. It tries to reduce the response time for a write request by deploying a two-level primary cache with a faster, smaller backup cache or a faster primary cache with a two-level backup cache. A comparative study of the results obtained for mirroring after deploying these caches over FC and iSCSI show that iSCSI provides adequate performance and reliability for a successful deployment of the mirroring application over it.