System and method for replicating data

A method for controlling the copying of information from a first logical volume to a second logical volume in a computer system, said method comprising:

• specifying a relationship between said first logical volume and said second logical volume;
• creating a copy of data in said first logical volume into said second logical volume;
• said creating a copy further comprising:
• copying data from said first logical volume to a first location into a memory;
• copying said data from said first location in said memory to a second location in said memory;
• copying said data from said second location in said memory to said second logical volume;
• wherein said copying said data from said first location in said memory to a second location in said memory is performed by a control unit substantially independently of a central processing unit.

A method for controlling the copying of information from a first logical volume to a second logical volume in a computer system, said method comprising:

• specifying a relationship between said first logical volume and said second logical volume;
• copying data read from said first logical volume into a memory located within a control unit and thereupon writing said data to said second logical volume;
• and
• wherein said copying said data from a first location in said memory to a second location in said memory is performed by a control unit substantially independently of a central processing unit.

A computer system comprising a plurality of storage devices, a control unit operable to control said storage devices, and a memory operable to temporarily store data read from said storage devices within said control unit, said storage devices addressable as at least one of a plurality of logical volumes, including a first logical volume and a second logical volume, said control unit operatively disposed to:

• establish a relationship between at least two of said logical volumes, said relationship defined between said first logical volume and said second logical volume;
• create a copy of data in said specified first logical volume into said second logical volume;
• said creating a copy further comprising:
• copy data from said first logical volume to a first location in said memory;
• copy said data from said first location in said memory to a second location in said memory;
• copy said data from said second location in said memory to said second logical volume;
• wherein said copy said data from said first location in said memory to a second location in said memory is performed by said control unit.

A computer program product for controlling the copying of information from a first logical volume to a second logical volume in a computer system, said computer program product comprising:

• code for specifying a relationship between said first logical volume and said second logical volume;
• code for creating a copy of data in said first logical volume into said second logical volume;
• said code for creating a copy further comprising:
• code for copying data from said first logical volume to a first location into a memory;
• code for copying said data from said first location in said memory to a second location in said memory;
• code for copying said data from said second location in said memory to said second logical volume;
• wherein said copying said data from said first location in said memory to a second location in said memory is performed by a control unit substantially independently of a central processing unit;
• and
• a computer readable storage medium for holding the codes.

A computer program product for controlling the copying of information from a first logical volume to a second logical volume in a computer system, said computer program product comprising:

• code for specifying a relationship between said first logical volume and said second logical volume;
• code for copying data read from said first logical volume into a memory located within a control unit and thereupon writing said data to said second logical volume;
• and
• wherein said copying said data from said first location in said memory to a second location in said memory is performed by said control unit substantially independently of a central processing unit;
• and
• a computer readable storage medium for holding the codes.

A control unit for controlling the copying of information, said control unit operable in a computing system comprising at least one of a plurality of storage devices, said control unit operable to control said storage devices, at least one of a plurality of processing units operable to access said control unit, said storage devices addressable as at least one of a plurality of logical volumes, including a first logical volume and a second logical volume, said control unit comprising a memory operable to temporarily store data read from said storage devices within said control unit, said control unit operatively disposed to:

• copy data read from said first logical volume into said memory located within said control unit;
• copy said data from said memory to a different location within said memory, changing a volume identifier associated with said data, and thereupon writing said data to said second logical volume;
• and
• wherein said copying said data from a first location in said memory to a second location in said memory is performed by said control unit substantially independently of a central processing unit.

A computer system comprising a plurality of storage devices, said storage devices addressable as at least one of a plurality of logical volumes, including a first logical volume and a second logical volume, at least one of a plurality of processing units, a cache memory operable to temporarily store data, and a control unit operable to store and retrieve data from said storage devices on behalf of said processing units;

• wherein said control unit is further operable to copy data from a first logical volume to a second logical volume according to a relationship established between said first logical volume and said second logical volume;
• wherein said control unit copies said data from said first logical volume to a first location in said cache memory;
• whereupon a data recovery unit within said control unit is operable to create a copy of said data in said first location in said cache memory to a buffer memory within said data recovery unit, and thereupon to copy said data from said buffer memory within said data recovery unit into a second location in said cache memory;
• and thereupon to copy said data from said second location in said cache memory to said second logical volume;
• wherein said data comprises a logical address section, said logical address section having a data content that is changed during said copying between said cache memory and said memory.

A computer system comprising:

• a first means for storing data;
• a second means for storing data;
• a cache means for temporarily storing data;
• a data recovery and reconstruction means for creating a copy of data from said first means for storing data into said cache means, and thereupon to create a copy of said data in said cache means into said second means for storing data,
• wherein said data comprises a logical address section, said logical address section having a data content that is changed by said data recovery and reconstruction means from a physical address corresponding to said first means for storing data to a physical address corresponding to said second means for storing data.

A method for creating a copy of data in a system comprising a plurality of storage devices, a control unit operable to control said storage devices, said control unit comprising at least one disk adapter and a memory operable to temporarily store data read from said storage devices within said control unit, said storage devices addressable as at least one of a plurality of logical volumes, including a first logical volume and a second logical volume, said method comprising:

• specifying a relationship between at least two of said logical volumes, said relationship defined between said first logical volume and said second logical volume;
• said at least one disk adapter creating a copy of data in said specified first logical volume into said second logical volume;
• said creating a copy further comprising:
• copying data from said first logical volume to a first location in said memory;
• copying said data from said first location in said memory to a second location in said memory;
• copying said data from said second location in said memory to said second logical volume.

A computer system comprising a plurality of storage devices, a control unit operable to control said storage devices, said control unit comprising at least one disk adapter and a memory operable to temporarily store data read from said storage devices within said control unit, said storage devices addressable as at least one of a plurality of logical volumes, including a first logical volume and a second logical volume, said at least one disk adapter operatively disposed to:

• establish a relationship between at least two of said logical volumes, said relationship defined between said first logical volume and said second logical volume;
• create a copy of data in said specified first logical volume into said second logical volume;
• said creating a copy further comprising:
• copy data from said first logical volume to a first location in said memory;
• copy said data from said first location in said memory to a second location in said memory;
• copy said data from said second location in said memory to said second logical volume.