Data storage unit with internal storage area network switch module and redundant data storage system including such data storage unit

A redundant data storage system, comprising:

• a first data storage unit, comprising:
• a first internal storage area network (SAN) switch module, comprising a first external transmission interface and a first internal transmission interface;
• a first storage server module, comprising a second external transmission interface and a second internal transmission interface;
• and
• a first storage device, wherein the first storage server module is respectively connected to the first storage device and the first internal transmission interface through the second internal transmission interface, the first internal SAN switch module is connected to the first storage device through the first internal transmission interface;
• and
• a second data storage unit, comprising:
• a second internal SAN switch module, comprising a third external transmission interface and a third internal transmission interface;
• a second storage server module, comprising a fourth external transmission interface and a fourth internal transmission interface;
• and
• a second storage device, wherein the second storage server module is respectively connected to the second storage device and the third internal transmission interface through the fourth internal transmission interface, the second internal SAN switch module is connected to the second storage device through the third internal transmission interface, wherein the second internal SAN switch module is connected to the second external transmission interface through the third external transmission interface, the second storage server module is connected to the first external transmission interface through the fourth external transmission interface.