Method and system to maintain data consistency over an internet small computer system interface (iSCSI) network

A computer program product comprising a computer-readable medium with instructions to enable a computer to implement a process for transferring data writes from a primary site to a secondary site, for disaster recovery purposes, said medium comprising:

• computer readable program code working in conjunction with a computer to insert a PiT marker beginning a PiT frame to be transferred;
• computer readable program code working in conjunction with a computer to log data writes in a primary journal, wherein said data writes are ordered in the point-in-time (PiT) frame;
• computer readable program code working in conjunction with a computer to insert a PiT marker indicating end of said PiT frame to be transferred;
• computer readable program code working in conjunction with a computer to iteratively obtain data writes saved in said PiT frame;
• computer readable program code working in conjunction with a computer to generate, for each data write to be transferred, a small computer system interface (SCSI) command;
• computer readable program code working in conjunction with a computer to transfer said generated SCSI command to said secondary site using the ISCSI protocol;
• and
• computer readable program code working in conjunction with a computer to save a data write encapsulated in the SCSI command in a secondary journal.

A method to maintain data consistency over an internet small computer system interface (iSCSI) network, said method comprising:

• copying content of a primary volume to a secondary volume;
• receiving data writes from at least one host;
• saving, simultaneously, said received data writes in a primary volume and in a primary journal, wherein said saved data writes in said primary journal are ordered in point-in-time (PiT) frames;
• and
• initiating, according to a predefined policy, a transfer of at least one PiT frame from said primary journal to a secondary journal, said transfer comprising:
• inserting a PiT marker in said primary journal, said PiT marker indicating end of said PiT frame;
• iteratively obtaining data writes saved in said PiT frame;
• generating, for each data write to be transferred, a small computer system interface (SCSI) command;
• transferring said generated SCSI command to a secondary site via the iSCSI protocol;
• and
• saving a data write encapsulated in said SCSI command in a secondary journal.

A computer program product comprising a computer-readable medium with instructions to enable a computer to implement a method maintaining data consistency over an internet small computer system interface (iSCSI) network, said medium comprising:

• computer readable program code working in conjunction with said computer to copy content of a primary volume to a secondary volume;
• computer readable program code working in conjunction with said computer to receive data writes from at least one host;
• computer readable program code working in conjunction with said computer to save, simultaneously, said received data writes in a primary volume and in a primary journal, wherein said saved data writes in said primary journal are ordered in point-in-time (PiT) frames;
• and
• computer readable program code working in conjunction with said computer to initiate, according to a predefined policy, a transfer of at least one PiT frame from said primary journal to a secondary journal, said transfer comprising:
• inserting a PiT marker in said primary journal, said PiT marker indicating end of said PiT frame;
• iteratively obtaining data writes saved in said PiT frame;
• generating, for each data write to be transferred, a small computer system interface (SCSI) command;
• transferring said generated SCSI command to a secondary site via the iSCSI protocol;
• and
• saving a data write encapsulated in said SCSI command in a secondary journal.

A system for maintaining data consistency over an internet small computer system interface (iSCSI) network, the system comprises at least:

• a network interface communicating with a plurality of hosts through a network;
• a data transfer arbiter (DTA) handling data writes transfer between a plurality of storage devices and the plurality of hosts;
• wherein said DTA further controls the process of maintaining data consistency;
• a device manager (DM) interfacing with the plurality of storage devices;
• and
• a journal transcriber transferring data writes from a primary site to a secondary site.