Computer system remote copying system and computer system

A computer system comprising:

• a first computer;
• a first storage system coupled to the first computer;
• a second storage system coupled to the first storage system;
• and
• a second computer coupled to the second storage system, the computer system performing remote copying from the first storage system to the second storage system,
• wherein the first storage system creates a first logical volume that is accessed by the first computer,
• wherein the second storage system creates a second logical volume in which a copy of the data stored in the first logical volume is stored,
• wherein the first computer executes a first operating system and a first program, and transmits a plurality of write data generated by the first program to the first storage system,
• wherein the second computer executes a second operating system and a second program,
• wherein the first operating system receives an enqueue request which is issued by the first program, specifics a first data object, and indicates the start of updating to ensure consistency of the first data object with the first program, and transmits a start marker request that includes information on the first data object to the first storage system,
• wherein the first operating system receives a dequeue request which is issued by the first program, specifies the first data object, and indicates completion of updating relating to the first data object, and transmits an end marker request that includes information on the first data object to the first storage system,
• wherein the first storage system receives the plurality of write data, the start marker request and the end marker request, and updates the data stored in the first logical volume using the plurality of write data,
• wherein the first storage system generates a plurality of transmission data including the plurality of write data, start marker information corresponding to the start marker request, end marker information corresponding to the end marker request, and a plurality of sequence information on the timing of receipt of the plurality of write data, the start marker information and the end marker information,
• wherein the first storage system transmits the plurality of transmission data to the second storage system asynchronously with the receipt of the plurality of write data,
• wherein the second storage system receives the plurality of transmission data,
• wherein the second storage system identifies, based on the sequence information, a series of write data included in the plurality of transmission data, relating to a second data object that is a copy of the first data object, and including the plurality of write data received by the first storage system after receipt of the start marker request and before receipt of the end marker request,
• wherein the second storage system transmits an update start notification that includes information on the second object to the second computer, in accordance with a judgment that the data stored in the second logical volume is to be updated using a part or all of the series of write data,
• wherein the second program issues an enqueue request that specifies the second data object to the second operating system, and if the enqueue request is successful, transmits to the second storage system a response to the update start notification via the second operating system,
• wherein the second storage system starts to update the data stored in the second logical volume using the series of write data, and, when updating of the data stored in the second logical volume is completed, transmits an update completion notification to the second computer, and
• wherein the second program issues a dequeue request specifying the second data object to the second operating system when the update completion notification is received.