Method and system for updating data in a data storage system

A system in a data storage system for updating stored data with received data in a cache associated with said data storage system, where said data storage system comprises N data storage drives, where data and calculated parity are striped across said N data storage drives for a stripe, said system comprising:

• a cache associated with said data storage system for receiving data;
• means for determining if said received data in said cache includes sequential data for a plurality of complete stripes;
• means for calculating parity for each of said plurality of complete stripes by logically combining only said received data for each of said plurality of complete stripe if said data is sequential for each of said plurality of complete stripes;
• means for coalescing said received data for each of said plurality of complete stripes and said calculated parity for each of said plurality of complete stripes;
• means for calculating parity for a particular stripe by logically XORing said received data and fetched data from said data storage system if said cache is not determined to include all sequential data contained within said particular stripe, where fetched data is fetched from said N data storage drives into said cache;
• means for coalescing said particular stripe with said plurality of complete stripes;
• and
• means for writing said coalesced data to each of said N data storage drives, such that input/output operations within said data storage system are minimized.

A method in a RAID data storage system for updating stored data with received data in a cache associated with said RAID data storage system, where said RAID data storage system comprises N data storage drives, where data and calculated parity are striped across said N RAID data storage drives for a stripe, said method comprising the steps of:

• receiving data into a cache associated with said RAID data storage system;
• determining if said received data in said cache includes sequential data for a plurality of complete stripes;
• calculating parity for each of said plurality of complete stripes by logically combining only said received data for each of said plurality of complete stripe if said data is sequential for each of said plurality of complete stripes;
• coalescing said received data for each of said plurality of complete stripes and said calculated parity for each of said plurality of complete stripes;
• calculating parity for a particular stripe by logically XORing said received data and fetched data from said RAID data storage system if said cache is not determined to include all sequential data contained within said particular stripe, where fetched data is fetched from said N RAID data storage drives into said cache;
• coalescing said particular stripe with said plurality of complete stripes;
• and
• writing said coalesced data to each of said N RAID data storage drives, such that input/output operations within said RAID data storage system are minimized.

A system in a RAID data storage system for updating stored data with received data in a cache associated with said RAID data storage system, where said RAID data storage system comprises N RAID data storage drives, where data and calculated parity are striped across said N RAID data storage drives for a stripe, said system comprising:

• a cache associated with said RAID data storage system for receiving data;
• means for determining if said received data in said cache includes sequential data for a plurality of complete stripes;
• means for calculating parity for each of said plurality of complete stripes by logically combining only said received data for each of said plurality of complete stripe if said data is sequential for each of said plurality of complete stripes;
• means for coalescing said received data for each of said plurality of complete stripes and said calculated parity for each of said plurality of complete stripes;
• means for calculating parity for a particular stripe by logically XORing said received data and fetched data from said RAID data storage system if said cache is not determined to include all sequential data contained within said particular stripe, where fetched data is fetched from said N RAID data storage drives into said cache;
• means for coalescing said particular stripe with said plurality of complete stripes;
• and
• means for writing said coalesced data to each of said N RAID data storage drives, such that input/output operations within said RAID data storage system are minimized.

A program product for updating stored data with received data in a cache associated with a data storage system, where said data storage system comprises N data storage drives, said program product comprising:

• a data processing system usable medium;
• a data updating program encoded within said data processing system usable medium that, in response to receiving data into said cache determines if said received data in said cache includes sequential data for a plurality of complete stripes,
• calculates parity for each of said plurality of complete stripes by logically combining only said received data for each of said plurality of complete stripe in response to determining that said data in said cache is sequential for each of said plurality of complete stripes,
• coalesces said received data for each of said plurality of complete stripes and said calculated parity for each of said plurality of complete stripes,
• calculates parity for a particular stripe by logically XORing said received data and fetched data from said data storage system in response to determining that said cache does not include all sequential data contained within said particular stripe, where fetched data is fetched from said N data storage drives into said cache;
• coalescing said particular stripe with said plurality of complete stripes;
• and
• writes said coalesced data to each of said N data storage drives, such that input/output operations within said data storage system are minimized.