Storage control method and system for performing backup and/or restoration

A storage control method implemented in a computer system comprising a computer, a first storage system connected to said computer, and a second storage system connected to said first storage system, wherein

• said second storage system comprises:
• a plurality of tape media for storing data;
• a first storage device capable of performing random access that is an access with randomly different access destinations at a rate higher than the tape medium;
• a virtual storage device that emulates said first storage device, and
• a second controller for controlling access to said plurality of tape media and said first storage device,
• said first storage system comprises:
• a second storage device for storing data;
• a third storage device having said virtual storage device mapped therewith, and
• a first controller for controlling data access to said second storage device or said third storage device;
• said second controller reserves a storage space on said first storage device, reads data from an object tape medium, which is a tape medium corresponding to said virtual storage device, of said plurality of tape media, to said storage space;
• said computer sends a Copy Indication to said first storage system;
• said first controller receives said Copy Indication from said computer, performs data copying between said second storage device and said third storage device in response to said Copy Indication and, at this time, sends a Data Access Command indicating said virtual storage device for data access generated in said third storage device to said second storage system, and
• when the Data Access Command relating to said virtual storage device is received from said first storage system, said second controller performs data access to said storage space, rather than to said object tape medium.

A computer system comprising:

• a computer;
• a first storage system connected to said computer;
• and
• a second storage system connected to said first storage system, wherein
• said second storage system comprises:
• a plurality of tape media for storing data;
• a first storage device capable of performing random access that is an access with randomly different access destinations at a rate higher than the tape medium;
• a virtual storage device that emulates said first storage device, and
• a second controller for controlling access to said plurality of tape media and said first storage device,
• said computer comprises a computer control unit for sending a Copy Indication to the first storage system,
• said first storage system comprises:
• a second storage device for storing data;
• a third storage device having said virtual storage device mapped therewith, and
• a first controller for controlling data access to said second storage device or said third storage device;
• said virtual storage device is provided in a plurality and a tape LU that is a logical storage unit is mapped with each of said plurality of virtual storage devices;
• at least two storage LU that are logical storage units are prepared in said first storage device;
• said first controller receives said Copy Indication from said computer, performs data copying between said second storage device and said third storage device in response to said Copy Indication and, at this time, sends a Data Access Command indicating said virtual storage device for data access generated in said third storage device to said second storage system,
• said second controller executes the following operations (A) through (F):
• (A) accepts a predetermined Prepare Indication with respect to each of said plurality of virtual storage devices from a higher-level device that is at least one of said computer and said first storage device;
• (B) when said Prepare Indication is received, and if in a tape medium having the end of an object tape LU mapped with an object virtual storage device that is indicated by said Prepare Indication there is present a tape LU different therefrom, considers the object tape LU and each of at least two tape LU including the different tape LU as object tape LU, reserves at least one storage LU that is released with a storage capacity equal to or larger than all the object tape LU, whereas when in a tape medium having the end of the object tape LU, no tape LU different therefrom is present, reserves at least one storage LU that is released with a storage capacity equal to or larger than the object tape LU;
• (C) reads data from said object tape LU into said at least one reserved storage LU;
• (D) performs data access to said at least one reserved storage LU, rather that to said object tape LU, when a Data Access Command relating to said indicated virtual storage device is received from said first storage unit;
• (E) accepts a predetermined End Indication corresponding to said indicated virtual storage device from said higher-level device;
• and
• (F) when receiving said End Indication, writes data present on said at least one storage LU into said object tape LU that serves as the data read source, and releases said at least one LU, and wherein
• in said (B), in a tape medium having the ends of said at least two tape LU, data of other tape LU are not present beyond the ends.