REDUNDANT ARRAY OF INEXPENSIVE DISKS (RAID) SYSTEM CONFIGURED TO REDUCE REBUILD TIME AND TO PREVENT DATA SPRAWL

摘要

A RAID system is provided in which, in the event that a rebuild is to be performed for one of the PDs, a filter driver of the operating system of the computer of the RAID system informs the RAID controller of the RAID system of addresses in the virtual memory that are unused. Unused virtual memory addresses are those which have never been written by the OS as well as those which have been written by the OS and subsequently freed by the OS. The RAID controller translates the unused virtual memory addresses into unused physical addresses. The RAID controller then reconstructs data and parity only for the unused physical addresses in the PD for which the rebuild is being performed. This reduces the amount of data and parity that are rebuilt during a rebuild process and reduces the amount of time that is required to perform the rebuild process. In addition, the RAID system is capable of being configured to prevent or reduce data sprawl.

主权项

1. A Redundant Array of Inexpensive Disks (RAID) system comprising:
a computer comprising at least a first processor; and a first local storage system, wherein an operating system (OS) of the computer runs on said at least a first processor and uses the first local storage system, wherein at least a file system (FS) and a filter driver also run on said at least a first processor, the FS using a portion of the first local storage system as virtual memory and maintaining a virtual memory table in the first local storage system, the virtual memory table comprising at least entries identifying virtual memory addresses in the virtual memory that are currently being used by the FS, wherein currently used virtual memory addresses are virtual memory addresses that have been written by the FS and that have not been freed by the FS subsequent to being written by the FS, the OS causing the virtual memory addresses that have been written by the FS and the corresponding data to be output from the computer; an array of physical disks (PDs); and a RAID controller interfaced with the computer and with the array of PDs, the RAID controller receiving, over the interface with the computer, the virtual memory addresses and the corresponding data, the RAID controller translating the virtual memory addresses into physical memory addresses in one or more of the PDs and writing the data to the corresponding physical memory addresses, and wherein in the event that a rebuild is to be performed for one of the PDs, the RAID controller identifies to the filter driver one or more virtual memory disks in the virtual memory that correspond to the physical memory address of the PD for which the rebuild process is to be performed, and wherein the filter driver scans a portion of the virtual memory table corresponding to the identified virtual memory disk or disks and identifies currently used virtual memory addresses and causes the currently used virtual memory addresses to be output to the RAID controller, and wherein the RAID controller translates the currently used virtual memory addresses into currently used physical addresses and causes data and parity to be reconstructed for the currently used physical addresses.