Computer system, and data migration method in computer system

A data migration method in a computer system including a plurality of storage apparatuses each including a storage device constituting a virtual device associated with a logical device, and a controller configured to manage the logical device, the method comprising:

• where a first logical device is included in a first storage apparatus and a second logical device is included in a second storage apparatus form a first HA (High Availability) pair;
• virtualizing the first logical device as a first virtual device included in a third storage apparatus, associating the first virtual device with a third logical device included in the third storage apparatus, virtualizing the second logical device as a second virtual device included in the second storage apparatus, and associating the second virtual device with the fourth logical device included in the second storage apparatus;
• forming a second HA pair which comprises the third logical device included in the third storage apparatus and the fourth logical device included in the second storage apparatus;
• after forming the second HA pair, migrating data in the first logical device included in the first storage apparatus to the third storage apparatus, managing the data in the third logical device, and managing data in the second logical device included in the second storage apparatus as data in the fourth logical device;
• changing an issuance destination of an input and output request of a host computer from the first logical device included in the first storage apparatus to the third logical device included in the third storage apparatus, and
• changing an issuance destination of an input and output request of the host computer from the second logical device included in the second storage apparatus to the fourth logical device;
• when the third storage apparatus receives a write request to the third logical device from the host computer, causing the third storage apparatus to store write-data for the write request in a cache memory included in the third storage apparatus, and destage the write-data to the first logical device of the first storage apparatus;
• causing the third storage apparatus to transmit an update copy request containing the write-data to the second storage apparatus;
• and
• upon receiving the update copy request, causing the second storage apparatus to manage the write-data in the update copy request as data that is not to be destaged to the second logical device of the second storage apparatus.

A computer system comprising a plurality of storage apparatuses each including a storage device constituting a virtual device associated with a logical device, and a controller configured to manage the logical device, the computer system further comprising:

• a first storage apparatus comprising a first logical device;
• a second storage apparatus comprising a second logical device configured to form a first HA (High Availability) pair with the first logical device;
• a third storage apparatus comprising a first virtual device in which the first logical device is virtualized, and a third logical device associated with the first virtual device;
• a fourth storage apparatus comprising a second virtual device in which the second logical device is virtualized, and a fourth logical device associated with the second virtual device;
• and
• a host computer;
• wherein the third storage apparatus and the fourth storage apparatus are configured to cause the third logical device included in the third storage apparatus and the fourth logical device included in the fourth storage apparatus to form a second HA pair,
• after the second HA pair is formed, the third storage apparatus is configured to migrate data in the first logical device included in the first storage apparatus to the third storage apparatus, and manage the data in the third logical device, and
• after the second HA pair is formed, the fourth storage apparatus is configured to migrate data in the second logical device included in the second storage apparatus to the fourth storage apparatus, and manage the data in the fourth logical device;
• the host computer is configured to change an issuance destination of an input and output request of the host computer from the first logical device included in the first storage apparatus to the third logical device included in the third storage apparatus, and change an issuance destination of an input and output request of the host computer from the second logical device included in the second storage apparatus to the fourth logical device included in the fourth storage apparatus;
• when the third storage apparatus receives a write request to the third logical device from the host computer, the third storage apparatus is configured to store write-data for the write request in a cache memory included in the third storage apparatus, and destage the write-data to the first logical device of the first storage apparatus;
• the third storage apparatus is configured to transmit an update copy request containing the write-data to the fourth storage apparatus;
• and
• upon receiving the update copy request, the fourth storage apparatus is configured to manage the write-data in the update copy request as data that is not to be destaged to the second logical device of the second storage apparatus.