System and method for ensuring merge completion in a storage area network
First Claim
1. A method for managing disk capacity allocated to a data log in a source data storage system during a merge process wherein data in the data log may be merged into corresponding data on a destination storage system connected to the source data storage system by at least one communication link, the method comprising the steps of:
- maintaining a ratio of merge writes out of the data log to writes from a host computer into the data log within a desired range until the write process reaches a predetermined distance from the end of the data log; and
quiescing writes from a host computer into the data log until the data log is fully written to the destination storage system.
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0 Petitions
Accused Products
Abstract
A data storage system adapted to maintain redundant data storage sets at a destination location(s) is disclosed. The data storage system establishes a copy set comprising a source volume and a destination volume. Data written to a source volume is automatically copied to the destination volume. The data storage system maintains a data log that may be activated when the destination volume is inaccessible due to, for example, a malfunction in the destination storage system or in the communication link between the source system and the destination system. I/O commands and the data associated with those commands are written to the data log, and after a destination system becomes available the information in the data log is merged into the destination volume to conform the data in the destination volume to the data in the source volume. The data log competes for disk capacity with other volumes on the system, and log memory is allocated as needed. During the merge process the system maintains the ratio of merge data writes out of the data log to data writes from a host computer into the data log within a desired range until the data log reaches a predetermined size, whereupon data writes into the data log are quiesced to permit the merge write process to complete.
190 Citations
18 Claims
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1. A method for managing disk capacity allocated to a data log in a source data storage system during a merge process wherein data in the data log may be merged into corresponding data on a destination storage system connected to the source data storage system by at least one communication link, the method comprising the steps of:
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maintaining a ratio of merge writes out of the data log to writes from a host computer into the data log within a desired range until the write process reaches a predetermined distance from the end of the data log; and
quiescing writes from a host computer into the data log until the data log is fully written to the destination storage system. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A computer program product for use in connection with a processor for managing disk capacity allocated to a data log in a source data storage system during a merge process wherein data in the data log may be merged into corresponding data on a destination storage system connected to the source data storage system by at least one communication link, comprising:
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logic instructions, executable on a processor, for maintaining a ratio of merge writes out of the data log to writes from a host computer into the data log within a desired range until write process reaches a predetermined distance from the end of the data log; and
logic instructions, executable on a processor, for quiescing writes from a host computer into the data log until the data log is fully written to the destination storage system. - View Dependent Claims (11, 12, 13, 14, 15, 16, 17, 18)
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Specification