Off-site real time data disaster backup system

The utility model relates to an off-site real time data disaster backup system, which comprises a master server and a plurality of slave servers, and is characterized in that a plurality of the slave servers are connected with the slave servers by an IP network; the slave servers provide a virtual disk to the master server by an ISCSI protocol; and a plurality of the virtual disks and a local disk are formed into a disk array by RAID technology in the master server, and the master server provides a virtual disk service by the ISCSI protocol. Therefore, all data which is written by the off-site real time data disaster backup system in the virtual disk of the master server is dispersedly and redundantly stored in each slave server, so as to achieve the purpose of long-distance IP backup. When a certain salve server crashes or a problem exists in a certain salve server, the data redundantly stored in other salve servers are normally used as before, so as to achieve the purpose of switching and taking over the ba