Remote copying system and remote copying method

A remote copying method in a remote copying system, the remote copying system comprising:

• a first site that includes a plurality of first site logical storage areas and sends data for which a write request is issued to the first site logical storage area and a second site that includes a plurality of second site logical storage areas and receives the data, wherein
• in order to achieve consistency between order of the write request and reflection order of the data in the second site on the second site logical storage area, a plurality of consistency groups that send and receive the data using respective independent sequence numbers per optional number of a pair of the first site logical storage area and the second site logical storage area, and the second site reflects the data that is received inside each of the consistency groups of which the sequence numbers are uniform, on the second site logical storage area, and
• when changing the consistency group to which a specific pair belongs,
• the first site, when the write request concerning the specific data is issued after the change, assigns the sequence number of the consistency group after the change to the data for which the write request is issued, retains sending, and starts sending the retained data, after notification indicating that the reflection of the data sent for which the write request is issued in the first site not later than a timing of the change in the consistency group before the change of the specific pair, on the second site logical storage area is terminated is received from the second site.

A remote copying method that transfers data from a first storage system including a storage in which a plurality of first logical storage areas may be formed to a second storage system that establishes a pair relationship with the first storage system and includes a storage in which a plurality of second logical storage areas may be formed, comprising:

• writing data to one of the first logical storage areas for which a write request for data is issued from a host in the first storage system;
• transferring the data that becomes an object of the write request from the first storage system to the second storage system;
• changing a consistency group in order to change the logical storage area included in the group, in the first storage system;
• writing the data transferred from the first storage system to the second logical storage area in which the pair relationship is established, in the first storage system;
• writing received data to the second logical storage area belonging to the consistency group before the change, among the received data, in the second storage system;
• determining whether the data has been written to the second logical storage area belonging to the consistency group before the change, in the second storage system;
• and
• writing the received data to the second logical storage area belonging to the consistency group after the change when the data has been written to the second logical storage area belonging to the consistency group before the change, as a result of the determination.

A remote copying system that transfers and stores data between a first storage system and a second storage system through a network, comprising:

• the first storage system including:
• a first storage for storing data in which a plurality of first logical storage areas are formed, and a first storage controller that performs input and output processing to the first logical storage area of the first storage in accordance with a request from a host, and controls transfer of the data to the second storage system, and
• the second storage system including:
• a second storage for storing data in which a plurality of second logical storage areas are formed, and a second storage controller that performs input and output processing to the second logical storage, and controls transfer of the data between itself and the first storage system, wherein
• the first storage controller performs control of changing a consistency group in order to change the logical storage area included in the group, in the first storage system,
• the second storage controls received data so as to be written to the second logical storage area belonging to the consistency group before the change, among the received data, and
• when whether the data has been written to the second logical storage area belonging to the consistency group before the change is determined, and, as a result of the determination, if the data has been written to the second logical storage area belonging to the consistency group before the change, the received data is controlled so as to be written to the second logical storage area belonging to the consistency group after the change.

A remote copying system that transfers and stores data between a first storage system and a second storage through a network, comprising:

• the first storage system including:
• a first storage for storing data in which a plurality of first logical storage areas are formed, and a first storage controller that performs input and output processing to the first logical storage area of the first storage in accordance with a request from a host, and controls transfer of the data to the second storage system, and
• the second storage system including:
• a second storage for storing data, in which a plurality of second logical storage areas are formed, and a second storage controller that performs the input and output processing to the second storage, and controls transfer of the data between itself and the first storage system, wherein the first storage controller including:
• means for changing a consistency group in order to change the logical storage area included in the group, in the first storage system;
• means for assigning a number of independent sequentiality per consistency group to the data written to the first logical storage area, and
• means for transferring the data that becomes an object of the write request to the first logical storage area, and information including the number to the second storage system, and
• the second storage controller including:
• means for controlling received data so as to be written to the second logical storage area belonging to the consistency group before change, among the received data;
• means for determining whether all numbers before the received number are uniform, in one consistency group;
• and
• means for controlling the received data so as to be written, which corresponds to the uniform number, to the logical storage area that belongs to the one consistency group and establishes a predetermined relationship when all the numbers are uniform as a result of the determination,
• the first storage controller and the second storage controller include a memory respectively, and store, in the memory, a first table that reflects consistency group management information including an ID that identifies a consistency group, information that indicates a state of the logical storage area in which a pair relationship is established, the most newly assigned number among the numbers assigned to data that is transferred to the second storage system in the consistency group, the oldest number among the numbers assigned to the data that is not transferred to the second storage system, the number concerning written data if the data whose number is uniform has been sequentially written to the second storage, and management information concerning the logical storage area in which the pair relationship is established and that is included in the consistency group, as well as a second table that reflects pair volume management information including the pair ID that identifies the pair relationship, information on the first logical storage area that is a duplicate source of remote copying data in the first storage, information on the second logical storage area that is the duplicate copy of remote copying data in the second storage, and pair information indicating a state of the pair relationship at least including a bitmap that indicates whether the data has been rewritten per predetermined unit of the first logical storage area in the first storage,
• the data transferred from the first storage system to the second storage system includes the ID that identifies the consistency group, the assigned sequence number of sequentiality, copying data information including the ID that indicates the logical storage area of each of a plurality of remote copying data information items, a data storage address, data length, and data, and migration information including a migration ID, a migration source flag and a migration target flag,
• the first storage controller turns on the migration source flag to data earlier than a consistency group migration period of time in the consistency group before the change, and transfers the data to the second storage system, and
• the second storage system checks the flag, and performs the control of writing the data to the second logical storage area when all the data of the sequence numbers before the sequence number of the data in which the flag turns on is uniform.