Target DASD controlled data migration move
First Claim
1. A method for migrating data to a target DASD from a source DASD coupled to a host, the source DASD including a source cache and a source non-volatile storage ("NVS"), the target DASD including a target cache and target NVS, said method comprising:
- electrically coupling the target DASD to the host;
electrically coupling the source DASD to the target DASD;
directing requests for access of data contained on the source DASD to the target DASD;
copying data stored in the source DASD to the target DASD by;
copying items of data stored in the source cache to the target cache; and
separatelycopying items of data stored in the source NVS to the target NVS;
concurrently with the copying steps, operating the target DASD to receive from the host requests for access to data stored in the source DASD, and in response to said receipt to satisfy the data access requests by performing steps comprising;
in response to a host read request for data, providing the requested data to the host from the target DASD if the requested data has already been copied from the source DASD, otherwise copying the requested data from the source DASD to the target DASD and then providing the requested data to the host from the target DASD; and
in response to a host request to write data, writing the requested data from the host to the target DASD if completion of the write request does not require data present in the source DASD but not present in the target DASD, otherwise copying the required data from the source DASD to the target DASD and then writing the requested data from the host to the target DASD.
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Accused Products
Abstract
Non-disruptive data migration moves are performed form a source DASD to target DASD in a data subsystem. Both source and target DASDs comprise a cache and a nonvolatile store (NVS). Relative to the host, the target DASD generally operates as a source, managing requests for access to source DASD data by issuing I/O requests to the source DASD. First, the target DASD initiates a background data transfer, where data is copied from the source DASD to the target DASD preparing the target DASD to replace the source DASD. The data transfer includes copying data items directly from the source DASD'"'"'s cache to that of the target DASD'"'"'s cache, as well as copying data items from the source DASD'"'"'s NVS to the target DASD'"'"'s NVS. During background data transfer, the host can still perform data access operations, such as reads and writes, using the target DASD. Namely, for data already copied from the source DASD to the target DASD, the host reads this data from the target DASD. Host requests to read data not yet copied to the source DASD causes staging of the data from the source DASD to the target DASD. For host write requests, the data to be written to the target DASD, if no source data is needed to complete the write. To satisfy host write requests requiring data not yet copied from the source DASD, the data is copied from the source DASD to the target DASD.
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Citations
70 Claims
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1. A method for migrating data to a target DASD from a source DASD coupled to a host, the source DASD including a source cache and a source non-volatile storage ("NVS"), the target DASD including a target cache and target NVS, said method comprising:
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electrically coupling the target DASD to the host; electrically coupling the source DASD to the target DASD; directing requests for access of data contained on the source DASD to the target DASD; copying data stored in the source DASD to the target DASD by; copying items of data stored in the source cache to the target cache; and
separatelycopying items of data stored in the source NVS to the target NVS; concurrently with the copying steps, operating the target DASD to receive from the host requests for access to data stored in the source DASD, and in response to said receipt to satisfy the data access requests by performing steps comprising; in response to a host read request for data, providing the requested data to the host from the target DASD if the requested data has already been copied from the source DASD, otherwise copying the requested data from the source DASD to the target DASD and then providing the requested data to the host from the target DASD; and in response to a host request to write data, writing the requested data from the host to the target DASD if completion of the write request does not require data present in the source DASD but not present in the target DASD, otherwise copying the required data from the source DASD to the target DASD and then writing the requested data from the host to the target DASD. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20)
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21. A method for migrating data to a target DASD from a source DASD, the target DASD being coupled to the host and the source DASD being coupled to the target DASD, the source DASD including a source cache and a source non-volatile storage ("NVS") the target DASD including a target cache and target NVS, said method comprising:
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directing requests for access of data contained on the source DASD to the target DASD; copying data stored in the source DASD to the target DASD by; copying items of data stored in the source cache to the target cache; and
separatelycopying items of data stored in the source NVS to the target NVS; concurrently with the copying steps, operating the target DASD to receive from the host data access requests and in response to said receipt to satisfy the data access requests by performing steps comprising; in response to a host read request for data, providing the requested data to the host from the target DASD if the requested data has already been copied from the source DASD, otherwise copying the requested data from the source DASD to the target DASD and then providing the requested data to the host from the target DASD; and in response to a host request to write data, writing the requested data from the host to the target DASD if completion of the write request does not require data present in the source DASD but not present in the target DASD, otherwise copying the required data from the source DASD to the target DASD and then writing the requested data from the host to the target DASD. - View Dependent Claims (22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34)
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35. A method for migrating data to a target DASD from a source DASD coupled to a host, the source DASD including a source cache and a source non-volatile storage ("NVS"), the target DASD including a target cache and target NVS, said method comprising:
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electrically coupling the target DASD to the host; electrically coupling the source DASD to the target DASD; electrically decoupling the source DASD from the host; copying data stored by the source DASD to the target DASD by performing steps comprising; receiving an identification of data items contained on the source DASD to be copied to the target DASD; creating a copy progress map including a listing of each identified data item, the copy progress map including for each data item an indicator denoting whether that data item has been copied from the source DASD to the target DASD; redirecting requests for access of data contained on the source DASD to the target DASD; operating the target DASD to repeatedly perform the following steps until all data items have been copied to the target DASD; selecting a data item whose indicator denotes that said data item has not been copied from the source DASD to the target DASD;
reading the selected data item from the source DASD;copying the selected data item to the target DASD by copying data stored in the source cache to the target cache and separately copying data stored in the source NVS to the target NVS; changing the indicator of the data item to denote that said data item has been copied from the source DASD to the target DASD;
satisfying any host data access requests received during the operating step by performing steps comprising;in response to a host request to read a data item, providing the data item to the host from the target DASD if the data item has already been copied from the source DASD, otherwise, copying the data item from the source DASD to the target DASD, providing the data item to the host from the target cache, and changing indicators corresponding to the copied data item to denote that said data item has been copied from the source DASD to the target DASD; and in response to a host request to write a data item from the host to the target DASD, writing the data item to the target DASD if completion of the write request does not require any data items present in the source DASD but not present in the target DASD, otherwise copying the required data items from the source DASD to the target DASD and then writing data from the host to the target DASD and changing indicators corresponding to the copied data items to denote that said data items have been copied from the source DASD to the target DASD.
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36. An article of manufacture comprising a data storage medium tangibly embodying a program of machine-readable instructions executable by a digital processing apparatus to perform method steps for migrating data from a source DASD to a target DASD, the source DASD including a source cache and a source non-volatile storage ("NVS"), the target DASD including a target cache and target NVS, said method steps comprising:
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directing requests for access of data contained on the source DASD to the target DASD; copying data stored in the source DASD to the target DASD by; copying items of data stored in the source cache to the target cache; and
separatelycopying items of data stored in the source NVS to the target NVS; concurrently with the copying steps, operating the target DASD to receive from the host data access requests and in response to said receipt to satisfy the data access requests by performing steps comprising; in response to a host read request for data, providing the requested data to the host from the target DASD if the requested data has already been copied from the source DASD, otherwise copying the requested data from the source DASD to the target DASD and then providing the requested data to the host from the target DASD; and in response to a host request to write data, writing the requested data from the host to the target DASD if completion of the write request does not require data present in the source DASD but not yet present in the target DASD, otherwise copying the required data from the source DASD to the target DASD and then writing the requested data from the host to the target DASD. - View Dependent Claims (37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49)
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50. An article of manufacture comprising a data storage medium tangibly embodying a program of machine-readable instructions executable by a digital processing apparatus to perform method steps for migrating data from a source DASD to a target DASD, the target DASD being coupled to the host and the source DASD being coupled to the target DASD, the source DASD including a source cache and a source non-volatile storage ("NVS"), the target DASD including a target cache and target NVS, said method steps comprising:
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receiving an identification of data items contained on the source DASD to be copied to the target DASD; creating a copy progress map including a listing of each identified data item, the copy progress map including for each data item an indicator denoting whether that data item has been copied from the source DASD to the target DASD; redirecting requests for access of data contained on the source DASD to the target DASD; operating the target DASD to repeatedly perform the following steps until all data items have been copied to the target DASD; selecting a data item whose indicator denotes that said data item has not been copied from the source DASD to the target DASD; reading the selected data item from the source DASD; copying the selected data item to the target DASD by copying data stored in the source cache to the target cache and separately copying data stored in the source NVS to the target NVS; changing the indicator of the data item to denote that said data item has been copied from the source DASD to the target DASD; satisfying any host data access requests received during the operating step by performing steps comprising; in response to a host request to read a data item, providing the data item to the host from the target DASD if the data item has already been copied from the source DASD, otherwise, copying the data item from the source DASD to the target DASD, providing the data item to the host from the target cache, and changing indicators corresponding to the copied data item to denote that said data item has been copied from the source DASD to the target DASD; and in response to a host request to write a data item from the host to the target DASD, writing the data item to the target DASD if completion of the write request does not require any data items present in the source DASD but not yet present in the target DASD, otherwise copying the required data items from the source DASD to the target DASD and then writing data from the host to the target DASD and changing indicators corresponding to the copied data items to denote that said data items have been copied from the source DASD to the target DASD.
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51. A data storage subsystem, comprising:
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a host; a source DASD, the source DASD including a source cache and a source non-volatile storage ("NVS"); a target DASD electrically coupled to the host and the source DASD, the target DASD including a target cache and target NVS, the target DASD being programmed for; directing requests for access of data contained on the source DASD to the target DASD; copying data stored in the source DASD to the target DASD by; copying items of data stored in the source cache to the target cache; and
separatelycopying items of data stored in the source NVS to the target NVS; concurrently with the copying steps, operating the target DASD to receive from the host data access requests for access to data stored in the source DASD and in response to said receipt to satisfy the data access requests by performing steps comprising; in response to a host read request for data, providing the requested data to the host from the target DASD if the requested data has already been copied from the source DASD, otherwise copying the requested data from the source DASD to the target DASD and then providing the requested data to the host from the target DASD; and in response to a host request to write data, writing the requested data from the host to the target DASD if completion of the write request does not require data present in the source DASD but not present in the target DASD, otherwise copying the required data from the source DASD to the target DASD and then writing the requested data from the host to the target DASD. - View Dependent Claims (52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69)
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70. A data storage subsystem, comprising:
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a host; a source DASD, the source DASD including a source cache and a source non-volatile storage ("NVS"); a target DASD coupled to the host and the source DASD, the target DASD including a target cache and target NVS, the target DASD being programmed for; receiving an identification of data items contained on the source DASD to be copied to the target DASD; creating a copy progress map including a listing of each identified data item, the copy progress map including for each data item an indicator denoting whether that data item has been copied from the source DASD to the target DASD; redirecting requests for access of data contained on the source DASD to the target DASD; operating the target DASD to repeatedly perform the following steps until all data items have been copied to the target DASD; selecting a data item whose indicator denotes that said data item has not been copied from the source DASD to the target DASD;
reading the selected data item from the source DASD;copying the selected data item to the target DASD by copying data stored in the source cache to the target cache and separately copying data stored in the source NVS to the target NVS; changing the indicator of the data item to denote that said data item has been copied from the source DASD to the target DASD;
satisfying any host data access requests received during the operating step by performing steps comprising;in response to a host request to read a data item, providing the data item to the host from the target DASD if the data item has already been copied from the source DASD, otherwise, copying the data item from the source DASD to the target DASD, providing the data item to the host from the target cache, and changing an indicators corresponding to the copied data item to denote that said data item has been copied from the source DASD to the target DASD, and in response to a host request to write a data item from the host to the target DASD, writing the data item to the target DASD if completion of the write request does not require any data items present in the source DASD but not present in the target DASD, otherwise copying the required data from the source DASD to the target DASD and then writing data from the host to the target DASD and changing indicators corresponding to the copied data items to denote that said data items have been copied from the source DASD to the target DASD.
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Specification