Patent ID: 7752389

Claim:
A method for determining where to store data and parity information in a RAID group for a data track having a track number comprising: providing a stripe number including said data track, said stripe number corresponding to a row of segments written to members of said RAID group, said row of segments including data and parity information, each of said members of said RAID group associated with a different member identifier; determining a first member identifier of a first member of said RAID group as a quotient of two elements, a first of said two elements being a remainder of said track number divided by a number of tracks in each stripe and a second of said two elements being a size of each of said segments, said first member identifying a RAID group member at which data information of said data track is stored; determining a second member identifier of a second member of said RAID group to store a first set of parity information for said data track, said second member identifier determined as a remainder of said stripe number divided by a number of members in said RAID group; determining a third member identifier of a third member of said RAID group to store a last set of parity information for said data track, said third member identifier being determined as a remainder of a sum divided by said number of members in said RAID group, said sum is a result of said second member and a number of parity members in said RAID group minus a value of one; determining whether said third member identifier is less than said second member identifier; and if said third member identifier is less than said second member identifier, updating said first member identifier to be a sum of a current value of said first member identifier, said third member identifier, and a value of one.