Abstract:

With the era of big data, SSDs (Solid State Disks) have been deployed in many largescale datacenters. As the most popular RAID technology, RAID5 has been used in SSD arrays in order to enhance the reliability. However, the parity information of RAID5 is frequently accessed, especially on random accesses dominated workloads. Frequent updating parity information degrades the performance as well as reduces the lifetime of SSD arrays. To solve this problem, the ParityAware SSD controller design is proposed. The ParityAware SSD controller gets the logical address of parity from RAID5 controller, and employs a cache, called Pcache, to store the updated parity. Data and parity are stored separately in the SSD. Experiment shows that, our method effectively reduces write operations of parity on SSD and the erase count, thus enhancing the performance and lifetime of SSD arrays significantly.

Key words: solid state disk, RAID5, parity information, SSD controller