System including a plurality of data storage devices connected via network and data storage device used therefor

• US 20080104444A1
• Filed: 10/02/2007
• Published: 05/01/2008
• Est. Priority Date: 10/05/2006
• Status: Active Grant

• Current Assignee: JP Morgan Chase Bank, N.A. (JP Morgan Chase & Co), Western Digital Technologies Incorporated (Western Digital Corporation)
• Original Assignee: Hitachi Global Storage Technologies Netherlands BV (Western Digital Corporation)
• Inventors: Takada, Hiroyuki, Takeda, Hiromoto, Kojima, Akira
• Granted Patent: US 8,078,921 B2
• Time in Patent Office: Days
• US Class Current: 714/6
• CPC Class Codes: G06F 11/1088 Reconstruction on already foreseen single or plurality of spare disks
• CPC Class Codes: G06F 2211/1057 Parity-multiple bits-RAID6, i.e. RAID 6 implementations
• CPC Class Codes: G06F 2211/1059 Parity-single bit-RAID5, i.e. RAID 5 implementations

Abstract

Embodiments of the present invention help improve the process for updating parities accompanied by the writing process. According to one embodiment, a host controller transmits a write command and new data to a hard disk drive (HDD). The HDD reads old data at a region where the new data are to be written. The HDD then XORs the new data and the old data to generate a pseudo-parity. The HDD sets the pseudo-parity in a data frame addressed to both of a horizontal parity disk drive HDD and a diagonal parity disk drive HDD and transmits it. The horizontal parity disk drive HDD and the diagonal parity disk drive HDD update the parities using the pseudo-parity.

Claims

1. A system comprising:

a first data storage device; and

a second data storage device connected to the first data storage device via a network, wherein

the first data storage device receives a first command for rewriting data of a designated address and a data frame corresponding to the first command,

the data frame includes a first data to be used for rewriting data according to the first command, a second command, and a destination of the second command,

the first data storage device rewrites the data of the designated address using the first data according to the first command, and transmits the second command and second data to be used for rewriting a parity related with the data of the address to the second data storage device which is the destination of the second command, and

the second data storage device rewrites the parity related with the data of the address using the second data according to the second command from the first data storage device.

2. The system according to claim 1, further comprising a third data storage device connected via the network;

wherein

the data frame further includes a third command and a destination of the third command; and

the third data storage device obtains the third command and the second data transmitted from the first data storage device and rewrites a parity related with the recorded data of the address using the second data according to the third command.

3. The system according to claim 2, wherein

the first data storage device transmits the third command and the second data obtained from the data frame to the third data storage device;

and

the third data storage device obtains the third command and the second data transmitted from the first data storage device and rewrites the parity.

4. The system according to claim 2, wherein

the first data storage device transmits a data frame to the second device, the data frame including the third command, a destination of the third command and the second data;

the second data storage device transmits the third command and the second data in the received data frame to the third data storage device; and

the third data storage device obtains the third command and the second data transmitted from the second data storage device, and rewrites the parity.

5. The system according to claim 1, wherein

the first data storage device generates the second data by XORing the first data to be written at the designated address and old data stored at the address;

and

the second data storage device generates a new parity by XORing the second data and an old parity stored beforehand.

6. A data storage device to be used in a system including a plurality of data storage devices connected via a network comprising:

a receiver for receiving a first command for rewriting data of a designated address, first data to be used in rewriting the data corresponding to the first command, and a data frame including a second command and a destination of the second command;

a controller for rewriting the data of the designated address using the first data according to the first command; and

a transmitter for transmitting the second command and a second data to be used for rewriting a parity related with the data of the address to the destination.

7. The data storage device according to claim 6, wherein the controller generates the second data by XORing the first data to be written at the designated address and old data stored at the address.

8. A system including a plurality of data storage devices connected via a network, generating a doubled parities by XORing unit data blocks of the respective data storage devices with respect to two different directions, and storing the parities, the system comprising:

a first data storage device which obtains a write command and new data, rewrites old data with the new data, generates a pseudo-parity by XORing the new data and the old data, and transmits a data frame including the pseudo-parity to two data storage devices which store parities corresponding to the old data;

a second data storage device which receives the data frame, obtains the pseudo-parity included in the data frame, generates a first new parity by XORing a first old parity corresponding to the old data and the pseudo-party, and stores the first new parity; and

a third data storage device which receives the data frame, obtains the pseudo-parity included in the data frame, generates a second new parity by XORing a second old parity corresponding to the old data and the pseudo-party, and stores the second new parity.

9. The system according to claim 8, wherein

the first data storage device receives a data frame which includes the new data, a second command, and a destination of the second command;

and

the second data storage device is the destination of the second command, generates and stores the new parity according to the second command transferred from the first data storage device.

10. The system according to claim 9, wherein

the data frame received by the first data storage device further includes a third command and a destination of the third command;

and

the third data storage device is the destination of the third command, generates and stores the new parity according to the third command transferred from the first data storage device.

11. A data storage device which is used in a system including a plurality of data storage devices connected via a network, generating doubled parities by XORing unit data blocks with respect to two different directions respectively, and storing the parities, the data storage device comprising:

a receiver for receiving a write command and new data;

a controller for rewriting old data with the new data and to generate a pseudo-parity by XORing the new data and the old data; and

a transmitter for transmitting a data frame including the pseudo-parity to two data storage devices which store parities corresponding to the old data.

12. The data storage device according to claim 11, wherein

the receiver receives a data frame including the new data, the second command, and a destination of the second command;

and

the transmitter transmits the second command to the destination to update the parities by using the pseudo-parity.