Data storage system with recently freed page reference state
AssigneeSeagate Technology LLC
InventorsDouglas Dewey, Ian Davies, Ryan Phillips
Life of this patent
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Abstract
A data storage system can connect a data storage controller to a host and a data storage device. A first reference state corresponding to a first zone of the data storage device can be incremented in response to a first version of data being assigned to the first zone by the data storage controller. A second version of the data may be written to a second zone of the data storage device prior to populating a recently freed list with the first zone having an incorrect reference state. The first zone can be allocated by the data storage controller for new data without altering the incorrect reference state that is subsequently written to the first zone as directed by the data storage controller.
Claims20
A method comprising:
- connecting a data storage controller to a host and a data storage device;
- maintaining a page table, reference table, and recently freed list separately with the data storage controller;
- incrementing a first reference state of the reference table corresponding to a first zone of the data storage device in response to a first version of data being assigned to the first zone by the data storage controller, the first reference state identifying the first zone as occupied with current data;
- writing a second version of the data to a second zone of the data storage device, the first zone subsequently having an incorrect reference state in the reference table;
- populating a recently freed list with the first zone;
- deciding, with the data storage controller, to not correct the first reference state corresponding to the first zone;
- allocating new data to the first zone without altering the incorrect reference state of the reference table;
- and
- writing the new data to the first zone as directed by the data storage controller.
A method comprising:
- connecting a data storage controller to a host and a data storage device;
- incrementing a first reference state corresponding to a first zone of the data storage device in response to a first version of data being assigned to the first zone by the data storage controller;
- writing a second version of the data to a second zone of the data storage device;
- evaluating a performance impact of updating the first reference state to a correct reference state with the data storage controller in response to the second version of data being written to the second zone;
- populating a recently freed list with the first zone having an incorrect reference state in response to the performance impact being greater than a predetermined threshold;
- allocating new data to the first zone without altering the incorrect reference state;
- and
- writing the new data to the first zone as directed by the data storage controller.
A system comprising a data storage controller connected to a host and a data storage device, the data storage controller configured to increment a first reference state stored in a reference table in response to a first zone of the data storage device written with a first version of data as assigned by the data storage controller prior to writing a second version of the data to a second zone of the data storage device, a recently freed list generated by the data storage controller is populated with the first zone in response to the second version of data being written and first zone causing the reference state of the first zone to be incorrect, the data storage device is configured to allocate new data to the first zone without altering the incorrect reference state.
Dependencies are inferred from the claim text.