【题目示意】     此题考ASM快速镜像同步的概念 【解析】     ● Disks         磁盘组创建时使用CREATE DISKGROUP 语句， 创建时允许我们设置冗余项：         NORMAL REDUNDANCY - Two-way mirroring, requiring two failure groups.         HIGH REDUNDANCY - Three-way mirroring, requiring three failure groups.         EXTERNAL REDUNDANCY - No mirroring for disks that are already protected using hardware mirroring or RAID.                 If you have hardware RAID it should be used in preference to ASM redundancy, so this will be the standard option for most installations.     ● Fast Mirror Resync        在短暂的磁盘故障发生时, ASM 保持跟踪记录那些要被写入掉线的磁盘中所改变的部分；        一旦磁盘再次可以使用时，那些改变的部分变被再次的同步到磁盘中， … [Read more...]