Offloading raid update operations to disk controllers

In a storage system including a redundant array of disks having an array controller, each disk of the redundant array of disks including a disk controller apart from the array controller, a method of updating data, the method comprising:

• receiving, by the array controller, a request to update particular data stored in a block on a particular disk of the redundant array of disks, the request including an input value;
• sending, by the array controller, the input value and an address of the block to the disk controller of the particular disk, this disk controller serving to i) generate a difference value which is a difference between the particular data and the input value, and ii) swap the particular data stored in the block on the particular disk with the input value;
• receiving, by the array controller, the difference values from disks storing payload data;
• computing, by the array controller, parity difference values;
• obtaining another block address on another disk of the redundant array of disks;
• and
• sending, by the array controller, the parity difference value to the disk controller of the other disk, this disk controller serving, ii) performing an addition operation on the delta value to data stored in the block at the given block address on the disk, and iii) replace data stored in the block at the given block address with the new data value.

A storage system constructed and arranged to update data stored on the redundant array of disks, the storage system comprising:

• a redundant array of disks having an array controller, each disk of the redundant array of disks including a disk controller apart from the array controller, each disk controller including:
• a data interface;
• memory;
• and
• a controller including controlling circuitry, the controlling circuitry being constructed and arranged to:
• receive, by the disk controller of a particular disk of the redundant array of disks, a request to update particular data stored in a block on the particular disk, the request including an input value;
• read the particular data from the block on the particular disk;
• perform, by the disk controller of the particular disk, an update operation on the particular bit data stored in the block on the particular disk, the update operation including a swapping operation involving the particular bit data and the input value and serving to produce an update result;
• and
• write, by the disk controller of the particular disk, the update result to the block on the particular disk.

A computer program product having a non-transitory, computer-readable storage medium which stores code for updating data stored on a redundant array of disks in a storage system, the redundant array of disks having an array controller, each disk of the redundant array of disks including a disk controller apart from the array controller, the code including instructions which, when executed by the disk controller, causes the disk controller to:

• receive, by the disk controller of a particular disk of the redundant array of disks, a request to update particular data stored in a block on the particular disk, the request including an input value;
• read the particular data from the block on the particular disk;
• perform, by the disk controller of the particular disk, an update operation on the particular bit data stored in the block on the particular disk, the update operation including a swapping operation involving the particular bit data and the input value and serving to produce an update result;
• and
• write, by the disk controller of the particular disk, the update result to the block on the particular disk.