Storage Virtualization Based Asynchronous Remote Mirror

Computerized data becomes more and more critical in todaypsilas digital life. With the help of redundant hardware and software, remote mirror can keep information systems alive by seamless service switching, even encountering site corruptions. Unfortunately, existing mirror systems have some limitations such as restrictions to specific storage devices and/or low level drivers. In this paper, we design a storage virtualization based asynchronous remote mirror system, named as SVAM (Storage Virtualization based Asynchronous Mirror). First, SVAM utilizes a logical volume structure, AMLV (Asynchronous Mirror Logic Volume), to provide data protection and make it the basic data container. This way, there is no device and driver dependency at all. Secondly, we present a server free mechanism to offload mirror related jobs to SAN IO nodes, therefore good performance can be expected. Finally, SVAM incorporates an advanced mirror protocol to support seamless service switching while keeping low network bandwidth overhead. Experiments and evaluation results demonstrate that SVAM has the ability to provide high reliability while only introduce little overhead: tolerated a site corruption while kept providing service, the cost was only 12.3% more time.