RAID Overlapping

Abstract

A first array of disk drives overlaps with a second array of disk drives in a Redundant Array of Inexpensive Drives (RAID) system, in which the first and second arrays share at least one disk drive. A first stripe of data from a first client is stored in the first array, and a second stripe of data from a second client is stored in the second array. The shared disk drives are less than the number of drives needed to reconstruct a full stripe. Thus, in the event of a drive failure in the first array, the first client can reconstruct the first data stripe, but is never able to reconstruct the second stripe. Likewise, in the event of a drive failure in the second array, the second client can reconstruct the second data stripe, but is never able to reconstruct the first stripe.

1 . A method comprising: 
 overlapping a first array of storage devices with a second array of storage devices, such that the first array and the second array of storage devices share at least one storage device;    storing a first stripe of data from a first client in the first array of storage devices; and    storing a second stripe of data from a second client in the second array of storage devices, wherein, in response to one of the storage devices in either the first array or the second array failing, the first array, including the shared at least one storage device, is able to reconstruct the first stripe of data but is unable to reconstruct the second stripe, and wherein the second array, including the shared at least one storage device, is able to reconstruct the second stripe but is unable to reconstruct the first stripe.    
   
   
       2 . The method of  claim 1 , wherein the first and second arrays of storage devices are in a Redundant Array of Inexpensive Drives (RAID) system.  
   
   
       3 . The method of  claim 2 , wherein the RAID system is a RAID5 system.  
   
   
       4 . A computer program product, residing on a computer usable medium, comprising: 
 computer program code for overlapping a first array of storage devices with a second array of storage devices, such that the first array and the second array of storage devices share at least one storage device;    computer program code for storing a first stripe of data from a first client in the first array of storage devices; and    computer program code for storing a second stripe of data from a second client in the second array of storage devices, wherein, in response to one of the storage devices in either the first array or the second array failing, the first array, including the shared at least one storage device, is able to reconstruct the first stripe of data but is unable to reconstruct the second stripe, and wherein the second array, including the shared at least one storage device, is able to reconstruct the second stripe but is unable to reconstruct the first stripe.    
   
   
       5 . The computer program product of  claim 4 , wherein the first and second arrays of storage devices are in a Redundant Array of Inexpensive Drives (RAID) system.  
   
   
       6 . The computer program product of  claim 5 , wherein the RAID system is a RAID5 system.