ShadowImage overview
Hitachi ShadowImage® (SI) uses local mirroring technology to create and maintain a full copy of a data volume within a Hitachi Virtual Storage Platform G200, G400, G600 (VSP G200, G400, G600) storage system.
You can use SI copies as backups, with secondary host applications, for data mining, for testing, as well as for other uses, while business operations continue without stopping host application input/output (I/O) to the production volume.