Most enterprise-level database applications use RAID disk arrays to improve disk access performance and data compatibility and fault tolerance. RAID can be roughly divided into several levels. SQL Server 2005 commonly uses several levels: 0, 1, 5, 10. Below I Let’s briefly talk about the differences between these levels and their applications.
RAID 0 is referred to as disk striping. It can provide the best read and write performance. If you make two disks into RAID0, then when writing data, you can write to disk A and disk B at the same time, so It can definitely improve read and write performance, but this also brings about a problem: if part of the data is lost, all your data will not be recovered, because RAID0 does not provide a redundant data recovery strategy. Therefore, RAID0 can be used on read-only database tables or copied databases. You can also use it if you are not sensitive to data loss. In short, this level is high-performance and non-redundant.
RAID 1 disk mirroring has no impact on reading. If there are two disks, it only affects writing, because it uses one disk as a redundant backup method. So if your two disks are 100G, then you can only Using 50G, this method will affect disk space usage and reduce I/O write performance.
The difference between RAID 5 and RAID1 is the addition of parity. All parity information will be spread across each disk, and the performance is higher than RAID1. However, once a disk I/O failure occurs, the performance will drop sharply. At the same time, this method is also a compromise between RAID0 and RAID1, and is a more general approach.
RAID 10 is a combination of RAID0 and RAID1. It provides high performance and high availability, and is better than RAID5 in performance. It is especially suitable for applications that write a lot, but the cost is relatively high. No matter how many disks you have, you will lose half of it. disk storage.