Fast data recovery from HDD failure
First Claim
1. A storage system comprising:
- a first storage device having a first plurality of hard disk drives and a first controller controlling the first plurality of hard disk drives;
wherein the first controller stores data in the first plurality of hard disk drives by stripes, the hard disk drives each include a plurality of parcels and the parcels each include a plurality of stripes, each stripe includes M data and N parity data, where M and N are integers, and the first controller calculates for each stripe the N parity data using the M data,wherein the M data and N parity data of the each stripe are allocated to M+N hard disk drives of the first plurality of hard disk drives,wherein a first hard disk drive of the first plurality of hard disk drives includes data or parity data of both a first stripe of the stripes and a second stripe of the stripes, while a second hard disk drive of the first plurality of hard disk drives includes data or parity data of only one of the first stripe of the stripes or the second stripe of the stripes,wherein during data recovery involving failure of one of the first plurality of hard disk drives as a failed hard disk drive, the first controller makes an allocation area based on the parcel, and copies data from the failed hard disk drive to the allocation area.
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Abstract
A storage system comprises a first storage device having a first plurality of hard disk drives and a first controller. The first controller stores data in the first plurality of hard disk drives by stripes. Each stripe includes M data and N parity data allocated to M+N hard disk drives of the first plurality of hard disk drives. A first hard disk drive includes data or parity data of both a first stripe of the stripes and a second stripe of the stripes, while a second hard disk drive includes data or parity data of only one of the first stripe or the second stripe. During data recovery involving failure of one of the first plurality of hard disk drives, the data in the failed hard disk drive is recovered for each stripe by calculation using data and parity data in other hard disk drives for each stripe.
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Citations
20 Claims
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1. A storage system comprising:
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a first storage device having a first plurality of hard disk drives and a first controller controlling the first plurality of hard disk drives; wherein the first controller stores data in the first plurality of hard disk drives by stripes, the hard disk drives each include a plurality of parcels and the parcels each include a plurality of stripes, each stripe includes M data and N parity data, where M and N are integers, and the first controller calculates for each stripe the N parity data using the M data, wherein the M data and N parity data of the each stripe are allocated to M+N hard disk drives of the first plurality of hard disk drives, wherein a first hard disk drive of the first plurality of hard disk drives includes data or parity data of both a first stripe of the stripes and a second stripe of the stripes, while a second hard disk drive of the first plurality of hard disk drives includes data or parity data of only one of the first stripe of the stripes or the second stripe of the stripes, wherein during data recovery involving failure of one of the first plurality of hard disk drives as a failed hard disk drive, the first controller makes an allocation area based on the parcel, and copies data from the failed hard disk drive to the allocation area. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. In a storage system which includes a first storage device having a first plurality of hard disk drives and a first controller controlling the first plurality of hard disk drives, a method of data recovery comprising:
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storing data in the first plurality of hard disk drives of the first controller by stripes, the hard disk drives each including a plurality of parcels and the parcels each including a plurality of stripes, each stripe including M data and N parity data, where M and N are integers, and the first controller calculates for each stripe the N parity data using the M data; allocating the M data and N parity data of the each stripe to M+N hard disk drives of the first plurality of hard disk drives, wherein a first hard disk drive of the first plurality of hard disk drives includes data or parity data of both a first stripe of the stripes and a second stripe of the stripes, while a second hard disk drive of the first plurality of hard disk drives includes data or parity data of only one of the first stripe of the stripes or the second stripe of the stripes; and during data recovery involving failure of one of the first plurality of hard disk drives as a failed hard disk drive, making an allocation area based on the parcel, and copying data from the failed hard disk drive to the allocation area. - View Dependent Claims (14, 15, 16, 17, 18, 19)
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20. In a storage system which includes a first storage device having a first plurality of hard disk drives and a first controller controlling the first plurality of hard disk drives, a non-transitory computer-readable medium storing a plurality of instructions for controlling a data processor to perform data recovery comprising:
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instructions that cause the data processor to store data in the first plurality of hard disk drives of the first controller by stripes, the hard disk drives each including a plurality of parcels and the parcels each including a plurality of stripes, each stripe including M data and N parity data, where M and N are integers, and the first controller calculates for each stripe the N parity data using the M data; instructions that cause the data processor to allocate the M data and N parity data of the each stripe to M+N hard disk drives of the first plurality of hard disk drives, wherein a first hard disk drive of the first plurality of hard disk drives includes data or parity data of both a first stripe of the stripes and a second stripe of the stripes, while a second hard disk drive of the first plurality of hard disk drives includes data or parity data of only one of the first stripe of the stripes or the second stripe of the stripes; and instructions that cause the data processor, during data recovery involving failure of one of the first plurality of hard disk drives as a failed hard disk drive, to make an allocation area based on the parcel, and copy data from the failed hard disk drive to the allocation area.
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Specification