Enhanced multi-pathing to an array of storage devices

An apparatus for storing and retrieving information from an array of storage devices implementing a plurality of virtual disk drives, the storage devices operatively coupled to a computer by a plurality of I/O paths, the apparatus comprising a virtual disk driver, executing on the computer, comprising:

• a scanner for finding available I/O paths between the computer and each storage device and for storing a list of the available I/O paths in a configuration file in a memory coupled to the computer;
• a receiver, for accepting I/O requests directed at a virtual disk memory location from an application executing on the computer;
• a module for mapping the virtual disk memory location to a corresponding storage device and for selecting an I/O path for the I/O request from the list of available I/O paths in the configuration file;
• a transmitter for sending the I/O request to the storage device over the selected I/O path;
• and
• wherein the virtual disk driver comprises a core virtual disk driver and a subordinate driver implementing storage array-specific functions, and the vitual disk driver further comprises a means for associating the core virtual disk driver with the subordinate disk driver in accordance with a switch table stored in the memory of the computer.

A program storage device, readable by a computer having a processor and a memory tangibly embodying one or more programs of instructions executable by the computer to perform method steps of storing and retrieving information from an array of storage devices implementing a plurality of virtual disk drives, the storage devices operatively coupled to the computer by a plurality of (I/O) paths, the method comprising the steps of:

• scanning the storage devices to find available I/O paths between the computer and each storage device;
• storing a list of the available I/O paths between the computer and each storage device in a configuration file;
• receiving an I/O request directed at a virtual disk memory location in a virtual disk driver;
• the virtual disk driver comprising a core virtual disk driver and a subordinate driver implementing storage array-specific functions;
• associating the core virtual disk driver with the subordinate disk driver in accordance with a switch table stored in a memory of the computer;
• mapping the virtual disk memory location to a corresponding storage device;
• selecting an I/O path for the I/O request from the list of available I/O paths in the configuration file;
• and
• transmitting the I/O request to the storage device over the selected I/O path.