What primary role does cache serve in a RAID system?

In a RAID (Redundant Array of Independent Disks) system, cache serves a crucial role by facilitating a temporary storage area for data that is in transition, specifically during the write operations. This cache allows the RAID controller to quickly store incoming data before it is written to the physical disks.

When data is written to the RAID array, instead of immediately writing it to the slower disks, the data first goes into the cache. This process enhances performance as the system can rapidly acknowledge the write request to the operating system while the actual disk write occurs in the background. This way, the RAID system can optimize throughput and improve write speeds.

Moreover, using cache helps to reduce latency, as it allows for better management of data flow and can handle bursts of write activity without overwhelming the disk drives. By mitigating the delay that would occur if each write operation had to wait for the slower physical disks, cache significantly improves the overall efficiency of the RAID system.