Patent ID: 7484039

Claim:
A method for replacing a failed disk with a spare disk in a networked storage system including but not limited to a grid storage system with a plurality of said controller nodes, comprising: providing a pool of spare disks in the storage grid storage system; providing message exchange protocols among the said storage controller nodes, wherein the said protocols communicate among the said storage controller nodes so that all said nodes are in synchronization on some desired state; providing pre-defined message exchanging sequence among the said nodes, the said sequence will be triggered when the said disk failure happens until the replacing process is complete, wherein the sequence is synchronized among all said controller nodes via the said protocols; providing a repair window synchronized among all said storage controller nodes to guarantee data access hazard will not happen while moving data within the said repair window, wherein the said repair window is communicated among the said controller nodes via the said message exchange protocols, the said window is advanced via the said message exchanging sequence until the said data movement is complete; providing a coordinator role to one of the said controller nodes, wherein the said coordinator node initiates and make decisions for the said message exchanging sequence to all said controller nodes, and is responsible to write critical data before the said data can be observed by other controller nodes; whereby the said replacing of failed disk will not interrupt regular storage access function at any time, and storage accesses can be processed by any of the said storage controller node with correct data, the level of redundant protection for the data on the said failed disk will be recovered after the said replacing is complete.