Research And Implementation Of Background Initialization For RAID

With the high-speed development of computer and internet technology, digitization of information has become an irreversible trend and profound changes in human society in all aspects of life. The extensive use of digital information and explosive growth of digital data make higher requirements to traditional data storage systems. RAID disk arrays greatly ease the bottlenecks caused by the shortage of performance and reliability of traditional storage systems.RAID disk array improves its system reliability by using the redundant data which needs to satisfy a certain relationship with the stored data. This relationship is known as data consistency. It is the data of RAID system meets data consistency that the system can get the capability of fault tolerance and recover. RAID initialization can help the system to meet the data consistency. Usually RAID initialization writes zero to the strip but the disadvantage of this approach needs to wait until the initialization completed to use the LUN that may cause economic losses to users.The background initialization can make the host I/O and initialization runs concurrently. LUN can be mapped to the host immediately after created. Based on the comprehensive analysis of existing programs of background initialization the thesis gives an improved program which has the following characteristics.①Can do I/O operations in parallel with the initialization; LUN can be mapped to the host immediately after created.②Use"Add-Zero Write"to process host I/O which can improve the performance of the host I/O.③Add host detection mechanism to the system which can avoid the competition for Disk Bandwidth between host I/O and initialization.Based on the Linux operating system the thesis completes the software design and implementation of the improved program. Experimental results show that the performance of the host I/O improves a lost during initialization.